# Question
Title: A case where Bishop for knight isn't a good trade
I have played recently a game. In the position below Stockfish is saying that **Nxe6** is a mistake and **Rad1** is suggested but I'm having a hard time figuring out why. Can someone provide some insights ? given these thoughts:

1. It's a bishop for knight in my favor.
2. The bishop makes my position slightly vulnerable because of the pin on the queen.
3. The knight outpost is appealing but it can be kicked with c5.

I played:

```
1r1q1rk1/ppn1bppp/2ppb3/8/2PNPBn1/1QN3P1/PP3PBP/R3R1K1 w - - 9 14

1. Nxe6 fxe6 2. Rad1

```

link of the game

# Answer
> 20 votes
> *it's a bishop for knight in my favor*

So what? You will have moved the knight 3 times to your opponent's bishop 1 move and you will have improved your opponent's position by opening the f file for him. So, not in your favour after all.

> *the bishop makes my position slightly vulnerable because of the pin on the queen*

No, it doesn't. If it ever becomes a threat you can nullify it with NxB. Until it becomes a threat you are reacting to a phantom.

> *the knight outpost is appealing but it can be kicked with c5*

To which you can react with NxB! Again, you are reacting to a phantom. Although Ndb5 would be much better increasing the pressure on the backward and now weak pawn on d6.

The reason you won the game is that your opponent blundered. His reply to your Rad1 of moving the knight back to f6 for no good reason was terrible. Far better would have been to kick your bishop with e5. With the knight on g4 protecting e5 this is possible and very good. With the knight back on f6 this is not possible.

As is often the case the move you chose, NxB, releases tension unnecessarily, and in this case in your opponent's favour. Playing Rad1 retains the possibility of NxB if it looks better later and it reinforces the center and places a rook opposite black's queen. It is just a much better move.

# Answer
> 6 votes
The statement "it's a bishop for knight in my favor" makes no sense, or at least, no more than "It's a knight for a bishop in my favor". Bishops are no better than knights. Well, they kind of are overall but the difference is so small that there are often many other factors that can turn the balance around.

Your knight is a very strong centralized piece, and it is true that it can be kicked away with ...c5, but at that point this would create a weakness (the d6 pawn) that can be targetted by your queen, dark-squared bishop and rooks.

And lastly, but probably most importantly, Nxe6 reinforces your opponent's central presence, while also activating the f8 rook

# Answer
> 1 votes
Nxe6 could also be followed by Nxe6, strengthening his king side, center presence as well as improving Black's queen, giving her more options. This is generally a waste of a well-positioned piece.

---
Tags: knights, bishops
---


# Question
Title: Why is the time control for FIDE chess tournaments what it is?
Now that from this answer, I know what the time control is, why is it 90 minute base time for the first 40 moves, an additional 30 minute base time for the rest of the game plus a 30 second increment for each move, and not a 2 hour base time with 30 second increments per move? It doesn't seem to make any sense. If the directors already have time to stay more than 4 hours and 41 minutes after the tournament begins, the maximum amount of time that could go by before the 41st move is completed, why are they rushing them to complete the 40th move a whole hour before then? They would still have the same amount of time to complete the 41st move if it was a 2 hour base time and 30 second increments. Are they specifically trying to rate them on their ability to play with that time control so that they'll know that the ones with a really high rating know how to adapt to playing well with that time control?

# Answer
We can't really answer what all the reasons for the decisions were, as there are many people involved with the committee that decides on the FIDE time controls and they haven't published their reasoning.

So I just want to point out two things:

One, history. A slightly older time control are for instance 2 hours for the first 40 moves, then 1 hour for the next 20 moves, then 30 minutes for the rest of the game. Before that, games were adjourned after move 60. Earlier time controls were similar but with more time per move. So there is a long tradition of time controls for parts of the game and not for a long time period for the whole game.

The reason is that organizers want to ensure that players have sufficient time left in each period of the game. As players don't know in advance whether their game will last 35 moves or 115, it's hard to decide how much time to use on the first 30 moves. A player who wants to have sufficient time left to play the endgame well has a middle game disadvantage against a player who just burns all his time assuming he doesn't reach that point. We want players to be able to play all parts of the game well so we add the time only if it is needed.

Another thing is to save time in case the game is short. Someone on the losing side of a game is going to use all his time to try to save it, so short games would take very long if all that time was given at the start. Tournaments are already very exhausting.
> 5 votes

---
Tags: tournament, fide, time-control
---


# Question
Title: Do some people play chess with a 5 minute base time and no increments because it's a different challenge than 3 minutes with 2 second increments?
Chess with a 5 minute base time and no increments is a very different game from chess with a 3 minute base time and 2 second increments. It probably always had a winner and a loser except for when there's a stalemate. The challenge pretty much is to form a clear plan on how to quickly react to each move your opponent could make and not get checkmated before your opponent's time goes to zero so that if your opponent is slow enough, you can win by moving faster than them and waiting until they run out of time.

# Answer
> 3 votes
> Chess with a 5 minute base time and no increments is a very different game from chess with a 3 minute base time and 2 second increments.

No, it isn't. Most of the moves in the two formats are played with the same aims and with the same mindset. Most games are decided before time becomes an issue. Only if the game is still undecided with little time left on the clocks does the increment make a difference.

In 5+0 flagging your opponent becomes an option based purely on time rather than position. You can have a completely even position but the player with a few seconds left will lose to the player with 30+ seconds left purely and simply because he can't move quickly enough and not for any chess reasons. In the same position in a 3+2 game that is not the case. Two seconds is ample time to make a move. Flagging still occurs, of course, but it is based on chess skill and ability. The player losing on time just can't solve the problems the other player sets him in the limited time available.

> It probably always had a winner and a loser except for when there's a stalemate.

This is just wrong. Many games in 5+0 result in draws because of repetition or perpetual check. They can also result in draws by agreement because neither side can see any winning chances, both players are short of time and neither player wants a lottery.

Timothy, do you actually play much chess? Because your questions are full of wrong assumptions which a regular player of the game would not make.

# Answer
> 0 votes
3:2 allows for the ability to gain time especially in online chess as you are able to perform pre-moves you can catch up quite a lot of time. I've once played a game where my opponent tried to flag me in a 3:2 game and then accused me of cheating - Never underestimate the incremental time!

See Wikipedia's page on Timing-methods

---
Tags: time-control, blitz
---


# Question
Title: Why is the Advance Variation considered strong vs the Caro-Kann but not vs the Scandinavian?
As title above, why is the Advance Variation in these recent years considered strong vs the Caro-Kann, especially owing to White's early space advantage in the center, but **not vs the Scandinavian?** In other words, the Advance Variation (especially the so-called Short System, with Nf3, Be2 etc.) is considered a strong way to fight the Caro-Kann. On the other side, after 1.e4 d5, the move 2.e5 is considered weak (or even a mistake) because Black can develop his Bishop to f5, obtaining a "better" version of the Advance French. But isn't the structure with ...Bf5 then very similar to the Advance Caro-Kann (which is considered strong)?

# Answer
> 14 votes
Against a white d4-e5 pawn formation, Black wants to play c5 (see e.g. the French opening). In the Caro-Kann, that will cost two moves (c7-c6-c5), while in the Scandinavian, it's only one move since the pawn is still on c7. That's one tempo, and as @Qudit notes in the comments, in the main line Scandinavian White usually *wins* a tempo by chasing the black queen around. So it's actually a difference of *two* tempi, which makes a huge difference, as is often the case in (semi-)open games.

---
Tags: opening, caro-kann, 1.e4, scandinavian-defense
---


# Question
Title: Has there been much research on rating inflation?
Magnus Carlsen's draw in yesterday's round of the 2012 London Chess Classic assured that his rating in the next published FIDE rating list will surpass Kasparov's previous record of 2851. I've seen/heard passionate chess fans debate the relative merits of Carlsen's rating achievement versus Kasparov's versus, say, Fischer's. *To be clear, that's not what I'm after here.*

One crucial element of such discussions is the notion of whether Elo ratings in general have undergone inflation over time: are there so many more 2700+ grandmasters today than there were 20 years ago because of a general rise in playing strength, or just because of some overall inflationary trend in the numbers? *I'm also not trying to solicit bare opinions about whether or not that's so.* What I am interested in knowing:

> What serious research attempts have been made to answer the empirical question as to whether FIDE Elo ratings have naturally inflated over time because of something other than a rise in overall strength in the player pool?

The Wikipedia entry on the Elo rating system has a little bit to say about the matter, and also points to an article by Jeff Sonas of Chessmetrics. In addition to any pointers to work by others, I, for one, would also welcome an answer that gives a clear, concise summary of Sonas' main points.

# Answer
> 23 votes
I am surprised that the paper "Intrinsic Chess Ratings" by Ken Regan and Guy Haworth hasn't been posted yet. It is exactly what's asked for, serious research into rating inflation. PDF

Basically they got games from three periods (1976-1979, 1991-1994, 2006-2009), in several rating ranges (e.g. both players within 10 points of 2200, within 10 points of 2300, etc), and excluded types of games that might be anomalous, like team matches. Read the paper, it looks quite thorough.

Then they compared the games systematically with Rybka 3.

Some sentences from the conclusion:

> We conclude that there is a smooth relationship between the actual players’ Elo ratings and the intrinsic quality of the move choices as measured by the chess program and the agent fitting. Moreover, the final sfit values obtained are nearly the same for the corresponding entries of all three time periods.

In my view, it's quite solid evidence against the existence of rating inflation.

# Answer
> 14 votes
I poked around some. You've probably seen these pages, but I'll post them anyway:

a. This page will interest you. It includes a photocopy of a letter from Elo himself stating the possibility:

> Thus over time the rating scale could drift unless some measures are taken to stabilize it.

He further mentions that the ratings scale has no anchor, no fixed point. Compare to an athlete who runs a race in an hour; an hour now is the same as an hour 50 years ago. *Time* is such a fixed point.

b. Also, hasn't the 'inflation' question already been answered by recent revelations of high ratings coming out of isolated areas? See the "Pool of Players" section of this page for an allusion to the issue. Additional support, though it is not scholarly nor particularly informative. Search for "isol". Here's another anecdote showing what happens with isolated populations (and another candidate for the 'why are chess players crazy' thread!) I didn't fact-check it but should be easy enough to do.

c. The Elo wiki article talks about inflation as if it's an accepted fact.

d. Here's a germane article about inflation, and the followup. Look at that smoking gun in 1986!

# Answer
> 6 votes
In absolute terms, Carlsen 2012 for sure is a stronger player than Kasparov 1985.

If Carlsen 2012 travelled in time played a match with Kasparov 1986, Carlsen would defeat Kasparov. This is simply because the technology-assisted preparation is a lot more efficient, and Carlsen has also an edge in opening theory, because he has the accumulated knowledge 1987-2012 that Kasparov does not have.

However, Kasparov is probably a stronger player than Carlsen. If we take the FIDE Top 100 List for June 2000 (the oldest one that can be obtained), we see that Kasparov with 2849 Elo competes with an average of 2641 for the 99 followers (Elo distance 208 points) while Calsen in Fide Top 100 for December 2012 with a 2848 Elo competes with an average of of 2702 for his 99 followers (Elo distance of 146 points).

Elo is about the difference of points, not about absolute values (100 points of difference for Elo mean that player A is 2 times better than player B, 200 points means 4 times better, and so on. So with that list, it meant that Kasparov was on average more than 4 times better than all his 99 followers, while Carlsen is probably less only 3 times better than the average of his 99 followers.

If we take the list were Kasparov has the maximum distance with his 99 followers and compare that distance with the best for Carlsen, we will be able to determine which player was actually the greatest, because with 99 data points, outliers (like another genius) get mitigate it.

I wonder however if Carlsen or Kasparov really care about who was better.

# Answer
> 4 votes
Elo's system had two components. One was independent of history, the other was not. His system for creating a "performance rating" over the course of an event or a period of time had no historical component to it; it was simply a measure of performance over the specified time. (Memory fails me on this point, but I *think* when he was calculating the ratings for FIDE this was the method he used.)

However the Elo system as used by federations around the globe does have a historical component, in that ratings are calculated by calculating a delta, a change from the previous rating.

The historically-based system has a natural tendency towards deflation. The system is a closed system, with no new points being created. So new players come in, take points from established players, and then exit (through death or retirement) before returning all those points back to the next batch of rising players.

Many ideas have been tried to compensate for this, some working better than others. Add to this the commercial pressure in the USCF of the early 70's to make ratings rise faster (the rather cynical view was that players would buy a book from the USCF and play in a tournament, their rating would go up, encouraging them to buy another book, etc.) and inflation was a real thing at some points in history.

Since Elo's system was based on a normal (bell) curve, it's nonsense to try and gauge inflation by measuring either extreme; the extremes are more likely to be affected by the total number of players being rated than by changes in actual strength or any sort of inflation.

# Answer
> 2 votes
I have a simple idea. Let's take a chess computer (hardware + software) that had it's rating measured 20 years ago, via play with other chess computers with known ratings that they had 20 years ago. Now let's measure it's rating now (exactly the same hardware plus exactly the same software), via play with modern chess computers, with known today's rating. The difference of two measurements would constitute rating inflation for the past 20 years. Simple enough?

# Answer
> 1 votes
The conclusions of Regan-Haworth paper should be taken with a grain of salt, as it seems to contradict other computer analysis of games, on better soft- and hardware and with more advanced mathematical methods. There they conclude (see Table 9), e. g., that Karpov in 1977 played at just slightly lower level than Kasparov in 2001 and Anand in 2008 (expected to score about 47% of points), and actually better than Topalov in 2005 and Ponomariov in 2011. Since Kasparov-2001 is 150 points higher rated than Karpov-1977, the rating would expect him to score 70% of points. I don't see how to reconcile this with the claim that there was no rating inflation.

Note that also, contrary to the implicit claim in the question, **there is no mechanism by which rating would reflect a change in the overall strength in the player pool**. It might be empirically the case that a typical strength of a 2600 player has not changed over certain time period, but this would be merely a coincidence rather than a reflection of fundamental properties of the ELO system, and certainly not generalizable.

If we rather define inflation naively and just measure the average rating of the top 100 players, then, as can be seen from this link, there was a steady inflation until 2012 and **no inflation since then - the top-100 average rating oscillated betweeen 2700 and 2705 for the last 7 years**.

# Answer
> 0 votes
First, you have to define what you mean by best. For example, does best mean you are the most dominant player for your era? Or does it mean that the quality of your player is superior to all other players. And if quality is what you mean, then how do you define quality?

Paul Morphy was probably the most dominant player. For example, when he was 12 years old he defeated a top ten player (Lowenthal) in a match 3-0. According to Edo and chessmetrics he was probably already one of the best players in the world at the age of 12! At the age of 21, he played against a simultaneous against 5 top ten players (Bird, Barnes, Boden, De Reviere, and Lowenthal) and scored 3-2.

However, most would argue that dominance is a poor indicator of who is best. After all, Morphy has been described as the first modern chess player. His competition was weak compared with subsequent champions.

Another definition that has been used is quality of play. However, this definition also has a lot of problems. In the 1900 hundreds , a number individuals argued that Steinitz or Lasker were the best players of all time arguing that their knowledge of opening and modern theory would make them superior to players from the past. However, Louis Paulsen made some very clever arguments against this hypothesis. He argued that Morphy (who had a photographic memory and memorized the Louisana bar code by the age of 19) if brought back to life would learn openings and modern theory within a year and be able to compete successfully against modern chess players.

Regan argues that modern chess players who have access to chess computers and modern training methods play more like computers than players of the past. That’s no surprise because they were trained by computers but does that mean that modern players are really better? This begs the question what would Fischer or Capablanca do if they had access to modern computers?

In addition, Professor Regan’s analysis computer strikes me as rather incomplete as it just involves a few five year periods and the players included in the analysis are not mentioned. A more thorough computer analysis by professors Matej Guid and Ivan Bratko found that in fact Capablanca played more like a computer than modern players! https://en.chessbase.com/post/computers-choose-who-was-the-strongest-player-. However, Guid and Bratko noted that there is a problem with concluding from this that Capablanca was a better player. Perhaps his rather sedate style led to fewer positions where he would be likely to blunder. Therefore, his blunder percentage was lower but he was also putting less pressure on his opponents than more aggressive players were. In fact, Capablanca had a high draw percentage compared with his contemporaries.

In contrast, a highly tactical player such as Kasparov might be penalized by his playing style which was more likely to lead to highly tactical positions where computers are especially good a finding errors. In fact, computers tend to perform better against tactical players than positional or in particular closed position players where tactics play a lessor role. Thus, computer analysis that relies on the number of computer detected errors is likely to favor sedate closed position players. In contrast, an aggressive player like Kasparov may make more tactical errors than some other players because he sought very complex positions but his opponents will make even more!

Therefore, you need an error weighting system that doesn’t just calculate the percentage of errors per 100 moves (which is basically what Regan and Guid and Bratko did ). Instead, you need to calculate the difference between your error rate and your opponents error rate. After all, chess is about committing fewer errors than your opponent. Putting pressure on your opponent to induce more errors is considered a good quality.

However, my revised calculation method leads to another problem which is these computer analyses don’t take into consider the strength of your opponent. For example, perhaps Larson achieves a very high chessmetrics rating because his aggressive (optimistic) style led to dominance over lower rated players. However, he had trouble in games against players of equal rating. Other players have frequently argued that he was too optimistic in his play against other high rated players. To avoid this problem, computer error checking analysis should only look at games against strong competors (e.g., the top 10, 20 or 100 players). However, that still doesn’t address the problem of increasing strong competition over time.

Can the problem of increasing quality of play be corrected by looking at back ratings such as Chessmetrics? Actually, I prefer the Edo back rating system http://www.edochess.ca/ because the statistical assumptions are better. For example, Chessmetrics assumes a player’s peak rating occurs when they are 40 years old. I doubt that is true for everyone and many players give up chess before that age or their play was only top notch for a few years (e.g., Harry Nelson Pillsbury, Charousek, Fischer, Morphy, Rubinstein, Fine). Unfortunately, Edo only compares players ratings from 1811 to 1920. According to Edo, Capablanca and Morphy are rated the two highest players from this era. According to Chessmetrics, Capablanca and Lasker were the two best players (Morphy doesn’t even make the top ten.) According to Chessmetrics, Zukertort, Steinitz, Tarrasch, Lasker, Pillsbury, Maroczy, Marshall, Janowsky, Chigorin, Schelecter, Blackburne, Duras, Teichmann, Neumann, Vidmar, Gunsberg, Rubinstein and Burn were better than Morphy. There are many other discrepancies between these two rating systems.

If innovation leads to dominance within a specific chess era over time and it becomes increasingly difficult to innovate over time as the strength of the competition increases you can’t measure true dominance by just looking at the match records of the top 30 players. That is, it’s a lot harder for Magnus Carlsen to dominate his opponents than it was for past champions. If you look at back ratings it’s easy to see that the magnitude of the difference between the top players’ ratings has been decreasing over time. So I believe an Edo type statistical model that takes into consideration the difficulty to dominate over time would be a better approach than what has been tried previously. For example, Fischer was a pretty dominant player for his era because he won 20 games in a row. What was Kasparov or Karpov longest winning streak compared with this winning streak? According to Seirawan, their longest winning streaks were seven games.

Of course, I’m not claiming that winning streaks are a good metric. I’m just arguing that dominance by ratings or in individual matches against other top players is a useful metric that isn’t explicitly taken into consideration in current back rating systems.

So my dream analysis is that you use Edo ratings based on a database that only includes the top 20 or 30 players from each five year period. After you complete this analysis you reweight your results by a dominance factor. That is, more recent players get a bonus factor that is calculated by estimating the trajectory of difficulty of dominating over time (the decrease in rating disparities between top 30 players over time). Next, you would validate this analysis by comparing players percentage of chess computer calculated blunders their opponents make minus their own blunders. If this invalidates the above, then you need to reweight according to the computer error checking analysis if it shows there is a tendency for more recent top players to play more accurately even after my dominance factor is taken into consideration.

My guess based on my eyeballing this, is that Kasparov would do very well. But that’s just a guess.

---
Tags: history, rating, fide, kasparov, carlsen
---


# Question
Title: How to evaluate and comment moves in PGN format?
I want, with Python-chess, to evaluate any movement of some game and generate the PGN with analysis, as Chess.com does in its analysis.

For example, i played one game with fools mate and they generate that PGN:

```
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "1-0"]

1. e4 f6 {INACCURACY (+1.03)} ({(+0.16) The best move was} 1... e6 2. d4 d5 3.
exd5 exd5 4. Bd3 Nf6 5. Nf3 Bd6 6. O-O O-O 7. Re1 Be6 8. h3 Re8 9. Nc3 c6 10.
Ne2 Qc7 11. Be3 Nbd7 12. Qc1 c5 13. c3 c4 14. Bc2 Ne4 15. Bf4 f6 16. Bxd6 Qxd6
17. Nd2 Nxd2 18. Qxd2 Nb6 19. Ng3 Bd7 20. Rxe8+ Rxe8 21. Re1 Rxe1+ 22. Qxe1) 2.
d4 g5?? ± {BLUNDER (♔ Mate in 1)} ({(+0.93) The best move was} 2... e6 3. Bb5
Ne7 4. Nc3 g6 5. Nf3 Bg7 6. h4 a6 7. Be2 d5 8. h5 gxh5 9. Rxh5 dxe4 10. Nxe4 f5
11. Nc5 Nbc6 12. c3 e5 13. dxe5) 3. Qh5# 1-0

```

I like to show the evaluation of any move (if its an good move, or excellent, blunder, book-move ...), like they do.

I know how to load any PGN game and process it, generating String from PGN, like:

```
import chess
import chess.pgn

pgn = open("game path")
board = game.board()
for move in game.mainline_moves():
    board.push(move)
exporter = chess.pgn.StringExporter(headers=True)

pgn_string = game.accept(exporter)
print(pgn_string) ## Here is the string with the pgn!

```

Basically: i want to generate a String PGN from an evaluated chess game.

# Answer
> 2 votes
For loading Stockfish using python-chess and evaluating a PGN input see these already answered posts:

For Adding comments in between moves according to standard PGN formatting, you can use `node.comment` as follows:

Let's take a sample PGN file (Svidler vs Caruana Grenke 2019) from TWIC, load it up and add a comment to the first move:

```
import chess
import chess.pgn

pgnfilename = 'samplepgn.txt'
with open(pgnfilename) as f:
    game = chess.pgn.read_game(f)

node = game.variations[0]
node.comment = 'this is a test comment'
print game

```

and the output is:

```
[Event "GRENKE Chess Classic 2019"]
[Site "Karlsruhe/Baden Baden GER"]
[Date "2019.04.20"]
[Round "1.2"]
[White "Svidler, Peter"]
[Black "Caruana, Fabiano"]
[Result "1/2-1/2"]
[WhiteTitle "GM"]
[BlackTitle "GM"]
[WhiteElo "2735"]
[BlackElo "2819"]
[ECO "B33"]
[Opening "Sicilian"]
[Variation "Pelikan (Lasker/Sveshnikov) variation"]
[WhiteFideId "4102142"]
[BlackFideId "2020009"]
[EventDate "2019.04.20"]

1. e4 { this is a test comment } 1... c5 2. Nf3 Nc6 ....

```

and if you want to write the output to a file (assuming `python 2.x`):

```
with open("testpgn.txt", "w") as fgame:
    print >> fgame, game

```

You should be able to take it from here. For any additional info, please have a look at the official documentations of python-chess.

# Answer
> 3 votes
Have you looked at python-chess-annotator? I think it does pretty much what you want, and if not, it might be easier to modify it than to start from scratch. It's based on `python-chess`, too.

I'll copy its usage example here to make this answer a bit more self-contained:

```
$ python3 -m annotator -h
usage: annotator [-h] --file FILE.pgn [--engine ENGINE] [--gametime MINUTES]
                 [--threads THREADS] [--verbose]

takes chess games in a PGN file and prints annotations to standard output

optional arguments:
  -h, --help            show this help message and exit
  --file FILE.pgn, -f FILE.pgn
                        input PGN file
  --engine ENGINE, -e ENGINE
                        analysis engine (default: stockfish)
  --gametime MINUTES, -g MINUTES
                        how long to spend on each game (default: 1)
  --threads THREADS, -t THREADS
                        threads for use by the engine (default: 1)
  --verbose, -v         increase verbosity

$ python3 -m annotator -f caruana-kasparov.pgn -g 15
[Event "Ultimate Blitz Challenge"]
[Site "St. Louis, MO USA"]
[Date "2016.04.29"]
[Round "18.1"]
[White "Fabiano Caruana"]
[Black "Garry Kasparov"]
[Result "0-1"]
[EventDate "2016.04.28"]
[ECO "A05"]
[WhiteElo "2795"]
[BlackElo "2812"]
[PlyCount "74"]
[Opening "King's Indian Attack: Symmetrical Defense"]
[WhiteACPL "252"]
[BlackACPL "141"]
[Annotator "Stockfish 8 64 POPCNT"]

{ Stockfish 8 64 POPCNT } 1. Nf3 Nf6 2. g3 g6 { A05 King's Indian Attack:
Symmetrical Defense } 3. Bg2 Bg7 4. O-O O-O 5. c4 d6 6. b3 e5 7. Bb2 c5 8. e3
Nc6 9. Nc3 Bf5 10. d4 e4 11. Ne1 Re8 12. Nc2 h5 13. Qd2 h4 14. Ba3 $6 { -1.13 }
( 14. h3 g5 15. g4 Bg6 16. Rad1 Qe7 17. Qe2 a6 18. Ba3 a5 { 0.19/25 } ) 14...
b6 $6 { -0.04 } ( 14... Nh7 15. Nd5 Ng5 16. Bb2 Rc8 17. Rac1 Ne7 18. Nf4 h3 19.
Bh1 { -1.11/24 } ) 15. Rfd1 $6 { -1.15 } ( 15. h3 d5 16. g4 Be6 17. cxd5 Nxd5
18. Nxe4 f5 19. gxf5 gxf5 { 0.00/26 } ) 15... Bg4 16. Rdc1 Qd7 17. b4 Qf5 18.
Bb2 Rad8 19. Nb5 Bf3 20. d5 Ne5 $6 { -1.66 } ( 20... Nxb4 21. Ne1 Bxg2 22.
Nxg2 Nd3 23. Nxh4 Qh3 24. Bxf6 Bxf6 25. f4 { -3.14/25 } ) 21. Bxe5 Rxe5 22.
Ne1 hxg3 23. fxg3 Bh6 24. Rab1 Kg7 $6 { -1.08 } ( 24... Qh5 25. Rb3 Rf5 26.
bxc5 dxc5 27. Rc2 Ng4 28. h3 Bxg2 29. Kxg2 { -2.48/24 } ) 25. Rb3 Qh5 26. h3
$6 { -3.08 } ( 26. bxc5 bxc5 27. Nxa7 Rh8 28. h4 Qg4 29. Nc6 Rh5 30. Qf2
Bd1 { -2.00/23 } ) 26... Nh7 $2 { -1.37 } ( 26... Rg5 27. Qf2 { -2.89/24 })
27. g4 Bxg4 28. hxg4 Qxg4 29. Qd1 $4 { -5.69 } ( 29. Qb2 Ng5 30. Nxd6 Qg3
31. Nf5+ gxf5 32. Kf1 Nf3 33. Qf2 Nh2+ { -2.30/24 } ) 29... Qg3 30. Qe2 Ng5
31. Kh1 Rh8 32. Nxd6 Kg8 33. bxc5 Bf8+ 34. Kg1 Nh3+ 35. Kf1 Bxd6
36. cxd6 Rf5+ 37. Nf3 Rxf3+ 0-1

```

(Note: I'm not the author or affiliated to this project in any way, so for further questions I suggest contacting the author via github.)

---
Tags: engines, analysis, software, programming, pgn
---


# Question
Title: Is it really possible to beat a stockfish level 8 computer in any time that is between 3+0 and 15+0?
I've watched a couple of games where people play against stockfish level 8 on lichess, and they pretty much lose all the time. Is it possible for someone to beat a level 8 computer in any time between 3+0 and 15+0?

# Answer
Assuming Stockfish level 8 is full strength Stockfish, it's *possible* to beat it but *extremely unlikely*.

In very rare cases, Stockfish will incorrectly evaluate a complicated position, unless given a minute or two to think. If a human were to get in such a position in a 3 0 game, Stockfish could make a fatal blunder.

However, the chances of the human making a mistake first is far greater.

Making the time control longer than 3 0 favors Stockfish, since it has more time to think if it's misevaluating something.

If Stockfish level 8 is only 2200-2400 (I've read this on some online sources), then beating it is more realistic.
> 3 votes

# Answer
IMHO playing against Stockfish level eight is a lost cause when playing against its full 16 quad core processors and basically unlimited flash storage, no matter the time constraints. Magnus Carlson stated a couple of years ago that he always lost against that computer program. The lichess version is but a shadow of its real self.
> 3 votes

# Answer
Yes, it is possibile and not so unlikely under two conditions:

1. the human is quite strong
2. lichess is browsed via mobile (not on a desktop pc)

Please note that the elaboration is not done serverside, but clientside. That means that it uses (part of) the resources of the hardware you are using when browsing lichess (!).

In other terms if you browse on a mobile the engine will be weaker.

Just today I drew a fast game (I’m near 2300 elo and I run it on a Samsung S8 hw).
> 2 votes

# Answer
Stockfish 8 **CANNOT** be beaten by a human in such fast time controls. Even strong GMs will face immense difficulty. It is definitely not impossible but it is highly improbable.
> 0 votes

# Answer
I used LiChess's Advanced Search feature to search for games with Stockfish level 8 playing blitz. Stockfish has lost against bots multiple times, but **I did not find any verifiable losses against humans**.

Some wins by Demolisher95 (; ; ) look like plausible human wins to me, with a kind of anti-Stockfish style, but the account states it uses "computer assistance", which makes these wins dubious.

There's a bunch of draws by strong players, e.g. Hungarian GM Gyula Pap achieved this draw (3+2 time control); a Ukranian IM achieved this draw (5+0 time control); a Dutch IM achieved this draw (5+3 time control); Russian FM Anton Maidel achieved this draw (5+3 time control); and so on. These draws were accompanied by multiple losses.

\[Some wins by thinkabit (; ; ; ), Widyana, SexyChessMen, Amir\_King1, and caballito64 are almost certainly with computer "assistance", so I disregard these wins.\]
> 0 votes

# Answer
This book lists blitz/rapid games won by a human against Stockfish:

https://www.amazon.com/Human-Versus-Machine-Stockfish-Komodo-ebook/dp/B0768G8R2C/

> My winning games against Stockfish and Komodo. This is for real. I have played over 50 thousand engine games, of which more than 10 thousand against Stockfish, and a large number against Komodo, so I have my fair share of wins. Read the book to learn what openings are suitable to handle the machines, how to impose your style of play, and how to approach the game in a tactically relevant way. The games are amply commented and diagrammed. You thought competition between humans and machines has already ended? Not at all, it has just started!
> -2 votes

---
Tags: stockfish, lichess
---


title: What is a pure checkmate?

text:
# Question
Title: What is a pure checkmate?
Recently I heard something about **pure checkmate**. This is a special kind of checkmate where each of the squares around the king has to be covered by just one single piece. One simple example of this would be checkmate using two pawns and the king:

```
[FEN "3k4/2PP4/3K4/8/8/8/8/8 w - - 0 1"]

```

Unfortunately, I couldn't find any more detailed information about this topic, which is the main reason for this question.

To make the question slightly more specific, I'd like to know what are the exact circumstances for a mate to be considered pure?

Is it allowed to have opponent's pieces involved in the check mate? For example like this:

```
[FEN "1r1q1r2/4R1p1/2p2pkp/p4Q1N/n2PP3/P5N1/5PPP/4R1K1 w - - 0 1"]

```

# Answer
> 11 votes
According to Wikipedia:

> "A pure mate is a checkmating position in chess in which the mated king and all vacant squares in its field are attacked only once, and squares in the king's field occupied by friendly units are not also attacked by the mating side (unless such a unit is necessarily pinned to the king to avoid it interposing to block the check or capturing of mating unit."

Essentially, a pure mate is a position in which each square around the opposing king is attacked only once by the mating side, so your first example is indeed a pure mate. However, your second example is not. While kings can be blocked off by their own units, they cannot be attacked unless they are pinned, which they aren't.

To summarize, the Black king can be surrounded by its pawns and pieces so long as they are not attacked, and if they are, they must be pinned. Furthermore, the pin must prevent the pinned piece from interfering with the mate.

As far as I can tell, multiple pieces may be on the board so long as the stipulations of a pure mate are met. The enemy pieces surrounding the king’s squares can be attacked, so long so as the mating piece is actually capable of mating, i.e. it cannot be captured or blocked.

Wikipedia gives an example from the final position from the famous Evergreen Game (link to chessgames.com).

```
 [Title "”The Evergreen Game,” Adolf Anderssen-Jean Dufresne. Berlin GER, 1852"]
[FEN "1r3kr1/pbpBBp1p/1b3P2/8/8/2P2q2/P4PPP/3R2K1 b - - 0 1"]

```

In this position, each of the Black king's available squares that it could move to are attacked exactly once by the White pieces, and the black blocking pieces are not attacked by white pieces at all. Although the White pawn that blocks off the g7 square for the black king is attacked, this is a real pure mate from high-level play nonetheless.

If you wish to see a constructed position for a pure mate, @DM has a great position in his answer to a related question on this site.

---
Tags: checkmate, problems, terminology
---


# Question
Title: Mutual Zugzwangs & Longest Checkmates (DTM, DTC and DTZ) in the endgame KRPP vs. KRP
Are there any surveys on mutual zugzwang positions and the longest checkmates (split into categories of DTM, DTC, and DTZ) in the endgame KRPP vs. KRP (King+Rook+2 Pawns vs. King+Rook+Pawn)? In particular, I would be interested in the full-point-mutual-zugzwangs in this endgame.

Unfortunately, the 7 men tablebases are not available for free online, and I do not know how I can download the required files (including all needed additional files due to the possibility of (under)promotions).

# Answer
I have been able to find information for everything asked of. However, I have not found any large surveys; just mere snippets.

---

1. Mutual Zugzwangs

This page on http://ruszchessstudies.blogspot.com/ provides several examples of half-point mutual zugzwangs along with some general information. Here is one of them.

```
[FEN "3K4/P7/P7/8/8/8/R5rp/3k4 w - - 0 1"]

```

As for full point mutual zugzwangs, one such position was given by @mbourzut in this a Rybka forum. This forum contains numerous drawing and winning positions; a small survey.

```
[FEN "8/8/2P5/2r1p3/RK1kP3/8/8/8 w - - 0 1"]

```

---

2. DTC

The record for the longest DTC sequence is 79 moves, according to page 24 of this arves.org PDF. It contains further information KRPP-KRP endgames.

```
 [FEN "8/r7/2K3p1/k7/8/8/P4P2/1R6 w - - 0 1"]

 1. Rb7 Ra6+ 2. Kc5 Ka4 3. Rd7 Ra5+ 4. Kd4 Rf5 5. Ke3 Kb4 6. Rd6 Re5+ 7. Kd4 Rf5 8. Rb6+ Ka3 9. Ra6+ Kb4 10. Ke3 Re5+ 11. Kf3 Rg5 12. Re6 Ka3 13. Re2 Kb4 14. Kf4 Rg2 15. Ke3 Rg1 16. Rc2 Re1+ 17. Kf4 Rg1 18. f3 g5+ 19. Ke3 Re1+ 20. Re2 Rc1 21. Rg2 Rc5 22. Rb2+ Ka3 23. Rd2 Rf5 24. Rc2 Kb4 25. Rc7 Kb5 26. Rc8 Re5+ 27. Kf2 Kb6 28. a4 Rd5 29. Rb8+ Kc6 30. Kg3 Rf5 31. Re8 Kd7 32. Re4 Rd5 33. Kg4 Kd6 34. Re8 Rc5 35. Kh5 Rf5 36. Re3 Ra5 37. Ra3 Kd7 38. Kg6 Ke7 39. Ra2 Ke8 40. Kf6 Kf8 41. Ra3 Ke8 42. Re3+ Kf8 43. Re4 Kg8 44. Ke7 Kg7 45. Kd6 Kf6 46. Kc6 Ra8 47. Kb5 Rb8+ 48. Kc4 Rc8+ 49. Kb4 Rb8+ 50. Ka3 Rh8 51. Re3 Rh3 52. Rb3 Ke7 53. a5 Kd8 54. Ka4 Rh4+ 55. Rb4 Kc8 56. a6 Rh6 57. Ka5 Rh7 58. Rb6 Rg7 59. Rb7 Rg8 60. Rb5 Rg7 61. Rb6 Rf7 62. Kb4 Rf4+ 63. Kb5 Rf5+ 64. Kc4 Rf4+ 65. Kd5 Kc7 66. a7 Ra4 67. Rf6 Kb7 68. Rf7+ Ka8 69. Ke5 Ra2 70. Rg7 Rg2 71. Ke4 Rg3 72. Ke3 Rg2 73. Kd3 Rf2 74. Ke4 Re2+ 75. Kf5 Re3 76. Kg4 Re4+ 77. Kg3 Rg4+ 78. Kf2 Rc4 79. Rxg5

```

---

3. DTM

The record for the longest DTM sequence is 218 moves. It can be found on page 105 of this PDF, created by Guy Haworth, about tablebase length records.

```
[FEN "8/k1P5/8/8/1R5P/7p/r7/1K6 b - - 0 1"]

1... h2 2. Kxa2 h1=Q 3. c8=R Qd5+ 4. Kb1 Qa5 5. Rcc4 Qe5 6. Ra4+ Kb6 7. Rc2 Kb5 8. Rac4 Qg7 9. Rc5+ Kb4 10. R2c4+ Kb3 11. Rc3+ Kb4 12. R5c4+ Kb5 13. Rc7 Qg1+ 14. Ka2 Qg2+ 15. Ka3 Qg1 16. Rb7+ Ka6 17. Rb2 Qa1+ 18. Kb3 Qe1 19. Rc6+ Ka7 20. Rc4 Qe6 21. Rbc2 Ka6 22. Ka4 Qd7+ 23. Rc6+ Ka7 24. Kb3 Qd5+ 25. Kb4 Qh1 26. Rc7+ Ka8 27. R7c4 Qh3 28. Ka4 Ka7 29. Rb4 Qd7+ 30. Ka3 Qd3+ 31. Kb2 Qd5 32. Rbc4 Qh1 33. Ka2 Qd5 34. Ka3 Qd6+ 35. Kb2 Qf6+ 36. Kb1 Qb6+ 37. Ka1 Qg1+ 38. Ka2 Qg8 39. Kb2 Qd8 40. Ra4+ Kb6 41. Rb4+ Ka5 42. Rbc4 Qh8+ 43. Kb3 Qg8 44. Ka3 Qf8+ 45. Rc5+ Ka6 46. h5 Ka7 47. Kb4 Kb6 48. Kb3 Qf3+ 49. Ka2 Qf7+ 50. Kb2 Qf6+ 51. R2c3 Qf2+ 52. Ka3 Qf8 53. Ka4 Qf1 54. Rc6+ Kb7 55. h6 Qa1+ 56. Kb4 Qb2+ 57. Rb3 Qd2+ 58. Kc5+ Ka7 59. Ra3+ Kb7 60. Rb6+ Kc8 61. Ra8+ Kc7 62. Ra7+ Kc8 63. Rc6+ Kb8 64. Ra4 Kb7 65. Rb4+ Ka7 66. Rc4 Qe3+ 67. Kd5 Qd2+ 68. Ke5 Qe3+ 69. Kf5 Qd3+ 70. Ke6 Ka8 71. Rc8+ Ka7 72. R8c7+ Ka6 73. h7 Qh3+ 74. Kf6 Qh6+ 75. Kf5 Qh3+ 76. Kf4 Kb5 77. Rc3 Qh1 78. Rb3+ Ka6 79. Rd7 Qh4+ 80. Ke5 Qg5+ 81. Kd4 Qf6+ 82. Kd3 Qg6+ 83. Kc3 Qg3+ 84. Kc2 Qg2+ 85. Kb1 Qf1+ 86. Ka2 Qe2+ 87. Ka3 Qe5 88. Rbd3 Qa1+ 89. Kb3 Qb1+ 90. Kc4 Qc1+ 91. Kd5 Qg5+ 92. Ke4 Qg4+ 93. Ke3 Qg5+ 94. Kf2 Qh4+ 95. Ke2 Qe4+ 96. Kd1 Qg4+ 97. Kc1 Qc4+ 98. Kd2 Qf4+ 99. Re3 Qf2+ 100. Kd3 Qf5+ 101. Kc3 Qc5+ 102. Kd2 Qa5+ 103. Rc3 Qa2+ 104. Ke3 Qe6+ 105. Kf2 Qb6+ 106. Re3 Qf6+ 107. Rf3 Qb6+ 108. Kg2 Qg6+ 109. Kf1 Qb1+ 110. Ke2 Qb5+ 111. Ke3 Qe5+ 112. Kd2 Kb5 113. Rdf7 Qd5+ 114. Ke2 Qe5+ 115. Kf1 Qh2 116. R3f4 Ka5 117. Ke1 Kb5 118. Kd1 Qh5+ 119. Kd2 Qd5+ 120. Ke2 Qe6+ 121. Kf2 Qh3 122. R4f5+ Ka4 123. Ra7+ Kb4 124. Rb7+ Kc4 125. Rc7+ Kb4 126. Rf4+ Kb5 127. Rfc4 Qh2+ 128. Ke3 Qh1 129. Kd2 Kb6 130. Kc2 Qa1 131. R4c6+ Kb5 132. Rc3 Qa2+ 133. Kc1 Qa1+ 134. Kd2 Qb2+ 135. Ke3 Qh2 136. Kd3 Kb6 137. R3c6+ Ka5 138. Rc5+ Kb4 139. Rc4+ Ka5 140. Kc3 Kb6 141. Kb3 Qh1 142. R4c6+ Kb5 143. Rc2 Qf3+ 144. Kb2 Qh1 145. Rf2 Qh4 146. Rf3 Qh2+ 147. Kb3 Qh1 148. Rf5+ Kb6 149. Rcf7 Kc6 150. R7f6+ Kd7 151. Kb2 Qh2+ 152. Kc3 Ke7 153. Rc6 Qg3+ 154. Kc2 Qg2+ 155. Kb3 Qg3+ 156. Rc3 Qb8+ 157. Kc4 Qc7+ 158. Kb4 Qb6+ 159. Rb5 Qd4+ 160. Kb3 Qd1+ 161. Ka3 Qa1+ 162. Kb4 Qb2+ 163. Kc4 Qh2 164. Kb3 Kd6 165. Rb7 Qh1 166. Rbc7 Ke5 167. R3c5+ Kd4 168. Kb2 Qh6 169. Rb5 Qf8 170. Rbb7 Ke4 171. Rc4+ Ke5 172. Rc3 Qf2+ 173. Kb3 Qh2 174. Re7+ Kd6 175. Rec7 Qh1 176. R3c5 Ke6 177. Kb4 Kf6 178. Rd7 Ke6 179. Rcd5 Qe1+ 180. Kb5 Qb1+ 181. Ka6 Qa1+ 182. Kb6 Qb2+ 183. Rb5 Qh8 184. Rb7 Kd6 185. Rf5 Ke6 186. Rh5 Qd4+ 187. Ka6 Qa4+ 188. Ra5 Qe8 189. Re7+ Qxe7 190. h8=Q Qd6+ 191. Kb5 Qd5+ 192. Kb4 Qd6+ 193. Rc5 Qb6+ 194. Rb5 Qd6+ 195. Kb3 Qd1+ 196. Ka3 Qd6+ 197. Rb4 Qd3+ 198. Ka4 Qc2+ 199. Rb3 Qc4+ 200. Ka5 Qc5+ 201. Ka6 Qc4+ 202. Rb5 Kd7 203. Qh5 Kd6 204. Qf5 Kc7 205. Qc5+ Qxc5 206. Rxc5+ Kd7 207. Kb6 Kd6 208. Rh5 Ke6 209. Kc6 Kf6 210. Kd6 Kg6 211. Rd5 Kf6 212. Kd7 Kf7 213. Rd6 Kf8 214. Ke6 Kg7 215. Ke7 Kg8 216. Kf6 Kh8 217. Kg6 Kg8 218. Rd8#

```

---

4. DTZ

The DTZ length records can be found in the Syzygy endgame tablebases. Here are the record positions without the moves.

```
[Title "Longest Winning DTZ, Without The 50-Move Rule-136 ply"]
[FEN "6k1/8/3pP1R1/3P4/8/1K6/8/3r4 b - - 0 1"]

```

---

```
[Title "Longest Winning DTZ, With The 50-Move Rule-100 ply"]
[FEN "2r5/8/8/2pP3K/2P5/3R2k1/8/8 b - - 0 1"]

```

---

```
[Title "Longest Losing DTZ, Without The 50-Move Rule-124 ply"]
[FEN "1k6/4K3/5R2/8/5P2/1p6/3P4/4r3 w - - 0 1"]

```

---

```
[Title "Longest Losing DTZ, With The 50-Move Rule-63"]
[FEN "8/8/8/K7/P5R1/1k6/P1p5/r7 b - - 0 1"]

```
> 3 votes

---
Tags: endgame, tablebases, rook-endgame, zugzwang
---


# Question
Title: Is this KBPP vs. KR position a draw or a win with perfect play?
I played a game on Lichess today as white, and me and my opponent reached this interesting endgame position.

```
[Title "Rewan Demontay-NN, Lichess, 5/14/19"]
[StartFlipped "0"]
[FEN "8/8/3r1kP1/5B2/4PK2/8/8/8 b - - 0 1"]

```

With Black to play, is this KBPP vs. KR position a draw or a win, with perfect play by both sides?

It looks like a draw to me. White can make no progress here. Black cannot exchange his rook for the bishop and a pawn at any point, or else the other white pawn will advance ahead and promote. Therefore, each side will effectively end up making infinite waiting moves. That is what happened in our game, and it was drawn by the 50 move rule.

Although I could use a computer, I wish to know how I can tell it is a draw without one.

# Answer
You're right, Black's dominance on the dark squares makes sure White cannot make any progress, and he only needs to sacrifice his rook for two pawns to ensure the draw. If he occupies the key squares for the last pawn, sacrificing the rook for the bishop and a pawn works too. (Of course, there's the immediate threat of e5+ winning the rook you need to protect against.)

Black shouldn't even be thinking of winning; the endgame KR vs. KB is a draw (unless the KB are badly placed) and as you can see in the position, it'll be very hard to force a pawn move from White, which would be necessary to win a pawn. Right now, everything is just too well protected.
> 0 votes

# Answer
IF White wanted to have any winning chances, the pawns should either be connected or, at least, staying in dark squares for quite some time. In the presented position, even if the central pawn pushes, Black will be able to blockade in the second rank
> 1 votes

# Answer
Yes it's a draw. It's hard enough for White to win these endgames with 2 split pawns if he had a *rook* instead of a bishop.
> 1 votes

---
Tags: analysis, learning, rook-and-minor-endgame
---


# Question
Title: How would I train like Bobby Fischer did?
As the title suggests, I want to know how to train like Bobby Fischer did, along with what books he read during his chess training. Remember, keyword is **TRAIN**. I don’t want to be **like** him, as that is impossible, but I merely want to know how to **train** like him.

# Answer
This question may be better suited for Worldbuilding Exchange, but as Bobby's training system you are asking for started at the precise second Bobby met the game at a young age, you will need to:

1. Return with a time machine to five years old and develop Asperger disorder.
2. Buy not only one but a dozen of chess boards.
3. Develop an uncontrollable obsession with chess as said, forgetting everything is not chess. Your mother can do those tasks and the school is totally unnecessary for you. You know modals and how the law rules, not to enter in troubles not related with chess.
4. Play millions of games with yourself. Play chess every minute you don't have to eat, sleep or waste your time with adults. Use those books only to follow master moves and remaster the games on your dozen of chess board that have colonized your home (you will need to convince your mother for that).
5. Go to the tournaments and destroy all those poor players that read the text of those chess books you will take a look later to see if they are correct or not.
6. Continue enjoying and learning at FIDE circuit your hole life.
> 1 votes

---
Tags: books, training, fischer
---


# Question
Title: Winning plan for black in this line of French Defense: Advance Variation Main Line
I play the French Defense as both white and black. I often play this line with black suggested by Korchnoi if I am not wrong. I have found a way to prevent the sudden b4, via Bd7 (if 8.Rb1 Bd7 9.b4 cxb3 10.Nxb3, I can answer with 10...Ba4, pinning the queen and winning material).

```

[FEN "r1b1kbnr/pp3ppp/1qn1p3/2ppP3/3P4/2P2N2/PP3PPP/RNBQKB1R w KQkq - 3 6"]

6. a3 c4 7. Nbd2 Na5

```

The problem is, although I feel comfortable with the limitations white has in development, I do not often find a winning plan as black and I end up finishing by playing for a draw.

What are your thoughts as to what I could do here?

# Answer
Once stuff has settled down on the queenside, you may eventually castle there and create play on the other sector, with moves such as ...f6 or ...f5 Take a look at a few illustrative games that may help you understand how to put this into practice
> 3 votes

---
Tags: strategy, positional-play, french-defense, planning
---


# Question
Title: Has anyone other than GM Axel Smith and GM Hans Tikkanen had success improving their chess through the "Woodpecker Method"?
The Woodpecker Method was introduced in the book *Pump Up Your Rating* (Google Books) by GM Axel Smith (FIDE), who was inspired by a training method used by GM Hans Tikkanen (FIDE), who used it to improve his chess. A subsequent book *The Woodpecker Method* (Google Books) was published by the two GMs.

A description of this method is given in Brian Towers's answer, but it involves repeatedly solving tactics problems (not only *what's the best move?* But, also, *what are the critical lines?*).

There's some debate online (see e.g. chess.com) as to whether this helped Axel Smith improve, or if this was attributable to other aspects of his chess training. Hence my question:

**Question**: Has anyone other than GM Axel Smith and GM Hans Tikkanen had success improving their chess through the "Woodpecker Method"?

# Answer
In the chapter *Woodpecker History* from the book *The Woodpecker Method*, Hans Tikkanen says this:

> I was obviously asked by many people about what I had done to finally take the step from IM to GM. I described the method and my rationale for adopting it, and several others decided to give it a go. One Swedish trainer has apparently invited his students in the north of our country to work dedicatedly on the method for a while.

But, tantalisingly, he does not name names.
> 4 votes

# Answer
What you describe as the Woodpecker method is a standard training regime many players do. Solving tactics over and over is one of the best ways to improve. Explicitly identifying all the critical lines can only help.
> 4 votes

---
Tags: training
---


# Question
Title: To what extent (if at all) is the new Komodo 13 MCTS an AlphaZero Lite?
The new Komodo 13 MCTS has been announced with the claim that:

> Komodo 13 MCTS thinks like no other chess engine in the world. Inspired by the ideas of AlphaZero and Leela, Larry and Mark set out to reinvent Komodo. What they came up with was Komodo 13 MCTS - a engine which searches for candidate moves in an incredible new way, and finds moves no other engine can

They are clearly trying to cash in on the publicity behind AlphaZero and LeelaZero. But is the hype justified?

There seems to be no mention of an AlphaZero like database of training results. Is the use of MCTS on its own enough to produce worthwhile improvements? More detailed information seems to be hard to find (possibly for commercial reasons).

# Answer
> 3 votes
There are a number of benefits to using MCTS instead of alpha-beta search, mainly in the realm of analysis.

Firstly, Alpha-Beta Search only attempts to find the best move in a position. As a result, MultiPV is implemented in alpha-beta engines by searching all the root moves, then searching the root again, skipping the root move, then searching again skipping the two already-found root moves, etc.

This significantly reduces the strength of alpha-beta engines in analysis, where you often want to take a look at multiple possible variations. MCTS, by contrast, expands out portions of the whole tree making the PV of every move considered by MCTS available. There is therefore no strength hit when enabling MultiPV for MCTS engines, and Komodo MCTS can therefore be much stronger than alpha-beta engines when MultiPV is set to high values.

With regards to the results of the search, MCTS has the advantage of being able to reflect the possibility of the opponent going wrong, as it assumes that all reasonable moves have some chance of being chosen. By contrast, alpha-beta engines always assume that the opponent will play the move that the engine considers best.

As a result, alpha-beta engines can often evaluate situations which are deadly tactical landmines to be dead draws, whereas Komodo MCTS can take this into account, further improving its performance in analysis of human games.

# Answer
> 4 votes
Komodo MCTS isn't a neural-network based engine. It just uses a different search algorithm, in particular MCTS instead of AB. Alphazero also used MCTS, so KMCTS is an "Alphazero lite" in that sense; however a distinguishing factor of Alphzero is that it uses a neural network to perform the evaluation, and KMCTS does not do that.

Is MCTS "better" than AB? Yes and no. From what I've seen, MCTS is exceptionally better when you want multiple PVs (because they effectively get it for free, while AB engines need to spend computational power). However MCTS loses firepower in tactical shoot-outs, and it's also really bad at winning a technical position. For example I remember seeing a KMCTS game in TCEC where its eval read "I have a forced checkmate" one move and then "wait, I don't, I only have a very large advantage" another, and then back to "I have a forced checkmate", etc.

Having said all that, KMCTS eliminated regular Komodo from the latest TCEC cup, so it's absolutely a respectable engine. In a straight-up game against another engine, it's not as strong as Stockfish or Leela, but it's comparable to everything else.

# Answer
> 3 votes
Komodo doesn't use machine learning, it just uses roughly the same search algorithm that A0/L0 uses. It still relies on the human-built heuristics it's used.

---
Tags: engines, alphazero
---


title: A question about piece development

text:
# Question
Title: A question about piece development
As opening principles say, you shouldn't push too many pawns in the opening. Instead, you should concentrate more on piece development. However, I have good example where it worked the other way around.

```
[FEN ""]
[Event "?"]
[Site "?"]
[Date "1984"]
[Round "?"]
[White "Emil Joseph Diemer"]
[Black "Tomas Heiling"]
[Result "1-0"]

1.d4 Nf6 2.f3 d6 3.e4 g6 4.g4 Bg7 5.g5 Nfd7 6.f4 c5 7.d5 b5 8.c3 a6 9.h4 Nb6 10.h5 e6 11.h6 Bf8 12.a4 exd5 13.a5 N6d7 14.exd5 Be7 15.c4 f6 16.cxb5 fxg5 17.f5 gxf5 18.Qh5+ Kf8 19.Nf3 Rg8 20.b6 Bb7 21.Nc3 Nf6 22.Nxg5 Nxh5 23.Ne6+ Ke8 24.Nxd8 Ng3 25.Nxb7 Nxh1 26.Bf4 Rg6 27.O-O-O Nf2 28.Re1 Kd7 29.Nb5 Ne4 30.Rxe4 Rg1 31.Re1 Rxf1 32.Rxf1 axb5 33.Rg1 Kc8 34.Nxd6+ Bxd6 35.Bxd6 Nd7 36.Rg8+ Kb7 37.Rg7 Kc8 38.Rxh7 Rxa5 39.b7+ Kxb7 40.Rxd7+ Kc8 41.h7 Ra1+ 42.Kc2 Kxd7 43.h8=Q Kxd6 44.Qd8+ Ke5 45.d6 1-0

```

Why did Emil win? He didn’t follow opening principles. Instead he did 17 consecutive pawn moves at the beginning.

# Answer
> 9 votes
Several reasons I can see:

* In closed positions like you have here, piece development is not as important as in open positions.
* To me it seems that black played his King's Indian set up, more or less ignoring what white is playing, which generally is not a good idea.
* Black should/could have attacked the center in the beginning more aggressively, thereby gaining space for his piece play. For instance 2. ... d5 would be natural (though likely he would have faced some version of the Blackmar-Diemer gambit). 5.... Nh5 would make any progress for white on the kingside very difficult.
* Until around move 16 black played OK and should not be worse. White has gained lots of space, but, if black plays 16... axb5 he does not have any weaknesses, while white's pawns are soon getting weak (a5 and g5 are hanging, ...)
* Around move 19, black has a clear advantage and should not have tried to hang on to the extra pawn but instead gone for active play, developing pieces, e.g. 19... Nf6 looks good.
* Black might have missed the knight fork on e6 (i.e. might have missed that white is not forced to move the queen after 21...Nf6). Because of this, the whole plan with Bb7, Nf6 loses strength, because it just helps white to develop the knight to c3 (while the bishop on b7 is still not all that great).
* 28...Kd7 is the final blunder, though admittedly white's Nb5 is not that easy to see

So in summary I'd say: Black played too passively and missed some tactics.

# Answer
> 2 votes
All general principles are subject to exceptions. If all you had to do in chess was memorizing a set of strategical guidelines and follow them all the time, chess would be a very boring game.

In this particular example, White's moves are not doing much for his own development, however they do disturb the opponent's. By move 13, Black and White have their respective developments at a similar stage. We can even argue that White pieces will have it easier to find good squares. Actually, the "developped" Black knight on d7 is not really doing anything but interrupting its teammates

---
Tags: opening, pawns, famous-games
---


# Question
Title: Is it OK to look at the list of played moves during the game to determine the status of the 50 move rule?
There are some positions in which you need to know how many moves have been played without pawn move or capture. For example:

```
[FEN "1R5K/8/8/8/8/8/7R/k7 w - - 98 1000"]

```

(1R5K/8/8/8/8/8/7R/k7 w - - 98 1000)

Here, white must play Ra2 or Rb1 to force a capture within 1 move. If this is not done the game is drawn due to the 50 move rule.

If the 50 move rule was not a concern it would be an easy mate in 2.

Of course it is very hard to remember how many moves have passed. Is white allowed to look at the scoresheet and count the number of moves during the game?

# Answer
> 13 votes
The rules for this and how it works are spelled out in articles 9.3, 9.4 and 9.5 of the FIDE Laws of Chess. They don't mention whether or not you are allowed to check your scoresheet to do this because you are **always** allowed to check your scoresheet. You would be very foolish to not check your scoresheet first because there are penalties for an incorrect claim.

Here are articles 93, 9.4 and 9.5 of the FIDE Laws of Chess:

> 9.3 The game is drawn, upon a correct claim by a player having the move, if:
> 9.3.1 he writes his move, which cannot be changed, on his scoresheet and declares to the arbiter his intention to make this move which will result in the last 50 moves by each player having been made without the movement of any pawn and without any capture, or
> 9.3.2 the last 50 moves by each player have been completed without the movement of any pawn and without any capture.
> 9.4 If the player touches a piece as in Article 4.3, he loses the right to claim a draw under Article 9.2 or 9.3 on that move.
> 9.5.1 If a player claims a draw under Article 9.2 or 9.3, he or the arbiter shall stop the chessclock (see Article 6.12.1 or 6.12.2). He is not allowed to withdraw his claim.
> 9.5.2 If the claim is found to be correct, the game is immediately drawn.
> 9.5.3 If the claim is found to be incorrect, the arbiter shall add two minutes to the opponent’s remaining thinking time. Then the game shall continue. If the claim was based on an intended move, this move must be made in accordance with Articles 3 and 4.

# Answer
> 4 votes
Yes you're absolutely allowed to look at the score-sheet.

What you're not allowed to do is make special symbols/notes on the scoresheet to remind you of things. But that's non-applicable here.

# Answer
> 1 votes
> Of course it is very hard to remember how many moves have passed. Is white allowed to look at the scoresheet and count the number of moves during the game?

In a serious tournament game, you would stop the clocks and ask the arbiter to come and check your scoresheets. I remember there was a recent incident between Russian GM Alexandra Kosteniuk against Chinese GM Ju Wenjun.

If there was no arbiter, you would have to do it with your opponents after stopping the clocks.

---
Tags: rules, 50-move-rule, claim-draw, scoresheet
---


title: Youngest and oldest active player

text:
# Question
Title: Youngest and oldest active player
Which currently active player is the youngest and which the oldest ?

Korchnoi is a candidate for the oldest, but I do not know if he is still active.

# Answer
**The answer to your question**

Korchnoi is alive. And playing! He played a match against Wolfgang Ulhmann last week (15-16 February 2015) in the Veterans section of the Zürich Chess Challenge. He won two games and lost two.

However, today (22 February 2015) the oldest active GM is the American Arthur B. Bisguier (Elo 2170) born in 1929. Korchnoi was born two years later.

But the most veteran player title is for Lourenço Joao Cordioli (Elo 1928), a Brasilian lawyer born in 1916. And he plays still; he actually got the 100th place in the Floripa Chess Open 2015 on January.

The youngest FIDE rated players are two boys born in 2010, an Indian boy rated 1036 and an Iranian boy rated 1340. I prefer not to give the names to protect their privacy, since they are so young.

The youngest GM is Samuel Sevian (Elo 2531, born in 2000), the youngest USA GM at the age of 13 years, 10 months, 27 days. There are also two WGMs born the same year: Zhansaya Abdumalik (Elo 2379) from Kazakhstan and Gunay Mammadzada (Elo 2334) from Azerbaijan.

**Some details on how I found the information**

To answer your question I have used the latest FIDE list of active players of February 12th 2015. But it has been more difficult than expected because of errors and missing data in the list.

For example, there was one player in the list born in 2049?! (maybe 1949?), another one in 205 (2005?), another in 1881 (1981?) and another in 1895 (1985?). Then, quite a lot of players had 0 or 1900 as birth year, which surely means that it is unknown.

And finally, according to the FIDE list there are 1 active player born in 2015 (?!), 3 born in 2014, 5 born in 2013, 3 born in 2012, 19 born in 2011... all of them unrated (of course). I confess I don't know what this means.

Anyway, I started looking for the oldest player. The first serious candidate was Carl Weibrecht (German, born in 1911, no FIDE rating). Although he appears as active in the list, I found a message in the website of Schachkreis Zugspitze dated May 1st 2011 saying

> "Chess Circle Zugspitze mourns chess friend Carl Weibrecht from Garmisch" (Google translated).

So he might not be active, after all...

The second candidate to the oldest player title was Dr. Horst Reichel, professor in Computer Science (also German, born in 1912, no FIDE rating). I have found some of his games for the period 2003-2006, but not later. So I am not sure if he is still playing. However, if the birthdate is correct he played till well passed 90 years old.

Then, there are other apparently active players born in 1915 (all without FIDE rating)... And at this point I decided to restrict the search to rated players and GMs.
> 7 votes

# Answer
Not the current youngest and oldest but back in 1990 I was board 2 for Wincanton chess club (England) in the East Somerset league. Boards 3 and 4 were 11 year-old Jack Rudd and 89 year-old RG Gray (*Mr.* Gray to relative youngsters like me ;-). Then the captain broke the bad news to me. Jack was being promoted and I was down to board 3. Suddenly I was playing between 2 players whose ages added up to 100 but with an age difference of 78. So, good candidates for the youngest and oldest to play at the same time for the same team.

Only in chess.

Note that Mr Gray had been playing chess long enough and at a high enough level that he played against Tartakover when he took refuge in England during the second world war and hence has a Morphy number of 3. Jack has beaten James Sherwin and hence has a Fischer number of 2.
> 2 votes

# Answer
The oldest chess player was Zoltan Sarosy. He lived 1906 - 2017 at 110 years. He was still playing actively in his centenarian years.
> 2 votes

# Answer
A good candidate for the oldest GM is Yuri Averbakh, (but not sure he is active anymore) see Wikipedia.

As for the youngest, I would say this guy.

As for Korchnoi, yes, he is still alive, see this interview on Chessbase.
> 1 votes

---
Tags: famous-players
---


# Question
Title: Eight pawns vs seven exercise: how to win?
I had been thinking about exercises to help players \<1400 gain confidence. For instance, they should feel confident they can always win with queen and king vs king, or rook and king vs king, even against Magnus Carlsen. They should also feel confident they can win with a bishop and 8 pawns vs 8 pawns.

So I lazily took all the pieces off the back ranks and removed black's king pawn, to give an exercise with king and 8 pawns vs king and 7 pawns. I figured winning a pawn up in a pawn endgame is a useful skill to know, and it should not be too hard.

```

[FEN "4k3/pppp1ppp/8/8/8/8/PPPPPPPP/4K3 w - - 0 0"]

```

However, initial desultory poking around showed Black may be able to sit tight and form a barricade. This could be instructive for a beginning player, but it also might be too intimidating.

While this probably won't happen in actual play (exchanged pieces mean there is probably at least one line open), this is a non-trivial case worth looking at, as Black could quite possibly establish a blockade down two pawns (you can ignore the two backwards pawns--I saw this pawn structure in a recent video of Ben Feingold's, about his 2019 Foxwoods tourney.)

```

[FEN "8/4k3/1p4p1/p1pPPp1p/P1P2P1P/8/4K3/8 w - - 0 1"]

```

What is a good strategy for White to minimize the possibility of blockades? Also, what is Black's best strategy to push pawns and maximize the possibility of blockades?

# Answer
> I figured winning a pawn up in a pawn endgame is a useful skill to know

It is a useful skill to know and an even more important skill to know is when a pawn-up endgame is a win and when it is a draw and when it could be either depending on who is to move first. This is a vital skill because it stops you from swapping off into a drawn king and pawn endgame when you are a pawn up.

> I had been thinking about exercises to help players \<1400 gain confidence.

When it comes to building confidence in pawn-up endgames for \<1400 players this is where you / they should start. This is a win for white if it is white's turn and a draw if it is black's turn.

```
[FEN "4k3/8/8/8/8/8/4P3/4K3 w - - 0 0"]

```

This teaches you the importance of:

* The opposition and
* Getting your king in front of your passed pawn not behind

In terms of preventing (or aiming for) drawing blockades the \<1400 player needs to know this position and why it is a win for white if it is white's turn and a draw if it is black's turn.

```
[FEN "8/ppp3k1/8/PPP3K1/8/8/8/8 w - - 0 0"]

```

This teaches you that it is the position of the pieces which is key not material balance. White to play wins by sacrificing a pawn or even two depending on black's response.

Finally, Capablanca's Position:

```
[FEN "6k1/7p/8/8/8/8/6PP/6K1 w - - 0 0"]

```

It is a win for white but if black knows the ending it is very easy for white to go wrong and end up in a drawn position. Many white players much stronger than 1400 would struggle to win this against a knowledgeable black opponent.

All 3 of the positions above could arise from the position in the question. All 3 have far fewer pieces and so are much simpler but are far from straightforward. Mastering them first would be a good first step.
> 6 votes

---
Tags: endgame, training, pawn-endgame
---


# Question
Title: A question regarding "The Horse Concoction"
Long ago in 2000, Tim Krabbe presented, a now classic, problem by Harry Goldsteen in his article “The Horse Concoction” on his site. It has blossomed across the Internet, as some of us know.

The task's stipulation is complex.

> Take an empty board. Put white pawns on b3, b6, h4 and h7, and a white Queen on f1. Now add ten black knights, both Kings, and the necessary material to enable White to stalemate Black in one move, and Black to win after any other move.

The retrograde analysis Tim Krabbe glosses over isn’t too hard to understand. But there is just one part that he skips over that nags at me, and I cannot figure it out.

Firstly, here is the unique position that solves the problem.

```
[FEN "8/7P/1P5B/2B1Q1n1/3nn2P/1PRnk1nR/3nnnK1/2B1nQBn w - - 0 1"]

```

Krabbe remarks that the knight jammed in the corner cannot be jammed in the corner on h8 for reasons too big for his article. But why is that so?

# Answer
> 3 votes
*This is just the very beginning of what must have been Goldsteen's demonstration, but if anyone wants to carry on from here...*

Let's try and build the position after White's key move.

The bNh8 cannot be pinned, so there must be "blockading" knights on f7 and g6, that are pinned themselves.

Because squares f7 and h7 are occupied, the bNg6 cannot be pinned diagonally. It cannot be pinned vertically either, otherwise we cannot pin the bNf7. Hence it is pinned horizontally, leftwards.

The bK cannot be on f6 because there wouldn't be enough space to set up a pin on the f6-h8 diagonal. It cannot be too far from the bNf7 either, so you can conclude that the bK stands on e6.

The space available (or lack thereof) allows us to define the positions of four more pinned knights and four pinning pieces, leading to this position:

```
[FEN "2B1R1Bn/3nnn1P/1PRnk1nR/3nn3/2B4P/1P6/8/5Q2 w - - 0 1"]

```

Two remarks:

* The wQf1 (*or even a wP, although it seems unlikely*) might have moved with the key move, I just put it on the diagram as a reminder that it had to be there before.
* Each wB or wR might be replaced by a wQ.

There will be two additionnal bN's, and two pinning pieces, on the e-file and on the e6-h3 diagonal.

To go further, I suppose we might discuss cases depending on the locations of these two bN's. A very important point is that Black must be winning if White doesn't stalemate, so most probably wK willl be under check by the 10th knight (as in the solution with a bNh1) to avoid allowing scores of possible first white moves. Most probably too, the bK will also have a free square to escape to, thus unpinning half of its army.

---

*Second step*:

White already has three promoted pieces on the diagram. Since adding two more of them would be illegal (due to the remaining four wP's), it means that one of the last pinning pieces must be either the wQ or the wPh7.

There are only five possible stalemating key moves to consider:

1. Ph7xNg8:B or Ph7xNg8:Q (these ones are very unlikely because they cannot be check-parrying moves)
2. Qf1xNh3
3. Qf1xNe1
4. Qf1xNe2

As a consequence, the positions of the wP's on b3, b6, and h4 are certain.

Let's consider that White's key move is 1.Qf1-takes-the-knight-that-was-checking-white-King and try now to infer where the wK might stand.

Given that the wK cannot be on f4 or g5 (these squares are controlled by other bN's), the available square that is closest to the cluster of black pieces is d4, with d3 and f3 second-order possibilities. Because it is very hard to imagine Black, who is down scores of material, to be winning against a far-away wK (say, on c1), putting the wK on d4 could be the most logical next step.

As a consequence, the pinned bN on the e6-h3 diagonal cannot be on f5, and must stand on g4. To limit wK freedom, it is tempting to put the 9th knight on e5 (controlling d3), but it might also be on e3 or e4.

Which leads to this diagram before the key move:

```
[FEN "2B1R1Bn/3nnn1P/1PRnk1nR/3nn3/2BK2nP/1P5B/4n3/5Q2 w - - 0 1"]

```

But this leads to several new difficulties:

* The key move 1.Qxe2 is **not** stalemating in spite of the 8 pins, since black can play 1...Kf6 or 1...Kf5. Of course, adding more (non-promoted) units, e.g. wNg3, wBg5, might still be possible. (Notice that if we add chosen the setup wKd3/bNe4/bNe1 instead, we would also need to cover square e5; but then, the bNg4 could be on f5 blocking one flight square...)
* We have to demonstrate a black win after the alternative capture 1.Bxe2, or make it impossible by adding a wNd3.

In both case, adding white units reduces the number of previous captures by Black, and is very likely to be impossible while keeping the legality of the position (less captures means less paths to promotions for both sides).

The alternative, in case adding a wB would still allow all the promotions, is:

```
[FEN "2B1R1Bn/3nnn1P/1PRnk1nR/3n1n2/2B1n2P/1P1K3B/8/B3nQ2 w - - 0 1"]

```

\[Ba1 could be on b2,c3,d4,g7\] \[If this is legal - *edit*: it is not\]

Then we really have a stalemate after 1.Qf1xe1, but demonstrating a Black win after the alternative 1.Ke2 is a long shot, since only two black units can move! The best try would be to put wBa1 on c3 and play 1...Nxc3+ followed by 2...Ke5 or 2...Kf6, but that would allow yet another variation starting with 1.Bxe1! And still... *(funnily enough, 1...Ng3+ 2.Kxe1 Nxf1 3.Kxf1 is another stalemate, and if Black cannot win the wQ at once he should not dream of a long-term win and has to checkmate quite forcefully)*

---

The third step should be retrograde analysis to prove that we cannot add a white knight nor a dark-squared bishop.

*Edit*: this step is actually pretty easy: Black needs three captures to promote all his pawns: one by the b-pawn, one by the h-pawn, and one by the e-pawn or the c-pawn to allow the opposing white pawn to promote on a light square.

As a consequence, the third diagram above is illegal. With a key move by the wQ, even without the stipulation that it should be the only move to prevent a defeat, I am thus unable to even reach a legal stalemate. *\[but I will not pretend I am 100% confident about all this reasonning; dear reader, please double check!\]*

The possible key moves that remain, because they allow more pieces to be present, are the non-check-parrying 1.h7xNg8:B and 1.h7xNg8:Q. I am pretty convinced that they cannot be mandatory to prevent defeat (and thus, that Harry Goldsteen **is** right - not a surprise!), but step four will be to...

---

Step four

*build a legal 9-knights stalemate starting with 1.h7xNg8:B*

I believe this is achieved by the following position:

```
[FEN "2B1R1nn/3nnn1P/1PRnk1nR/3nn3/2BK2nP/1P5B/8/4RQ2 w - - 0 1"]

```

1.h7xNg8=B **is** stalemate

However, Black is clearly not winning after any other White move. Indeed, White has a direct mate in 1 with

1.Bxg4# or 1.Bxd5#

Convincing oneself that it is really mate is a little mind-boggling with all these pinned defenders who cannot defend.

I may spend a bit more time and sweat to prove properly that this last position is legal, but I will stop thereafter. After reaching that point, I am totally convinced that Goldsteen's assertion that *"there is no solution to the Horse Concoction with a bNh8"* is absolutely correct.

**Addendum**

Here is a game that proves the position is legal. Due to the page freezing, it can be played out on apronus.com.

Move List: 1. a4 a5 2. h4 h5 3. g4 e5 4. g5 Rh6 5. gxh6 d5 6. f4 Bd6 7. d4 e4 8. Na3 g5 9. Nc4 e3 10. Nd2 exd2+ 11. Kf2 Be5 12. dxe5 g4 13. e4 Qg5 14. fxg5 f5 15. b3 Ra6 16. Ba3 b5 17. h7 Rb6 18. g6 b4 19. g7 Rb5 20. axb5 bxa3 21. c4 c5 22. Nh3 Bd7 23. b6 Bb5 24. cxb5 g3+ 25. Ke2 g2 26. Nf2 f4 27. Ng4 hxg4 28. b7 f3+ 29. Ke3 d4+ 30. Kf4 g3 31. e6 f2 32. e5 g1=N 33. Bh3 g2 34. e7 Kf7 35. e6+ Kf6 36. e8=B a2 37. e7 a4 38. Bf7 a3 39. e8=B c4 40. Bed7 c3 41. Bc8 Nd7 42. b8=R d3 43. Bb7 c2 44. Re8 Ne7 45. Bc4 f1=N 46. g8=R c1=N 47. b6 Nf3 48. Bb5 Nfe5 49. Qe1 Nf7 50. Rh2 g1=N 51. Rb1 d1=N 52. Rg5 Nf2 53. Rh5 Ng4 54. Rc2 d2 55. Ke4 d1=N 56. Rcc5 Nc3+ 57. Kd4 Ncd5 58. Bc4 Nfe3 59. Rb2 N3f5+ 60. Ke4 N5h6 61. Kd4 Nhg8 62. Ke4 a1=N 63. Rd2 Nf3 64. Qe2 N3e5 65. Qe1 N5g6 66. Qe2 Ngh8 67. Qe1 Nc2 68. Qe2 Ne1 69. Rd1 a2 70. Qg2 a1=N 71. Qg1 Nac2 72. Qf1+ Ke6 73. Bc8 Nce3 74. Kd4 N3f5+ 75. Ke4 N5d6+ 76. Kd4 Ncd3 77. Rc6 N3e5 78. Rc1 N1d3 79. Re1 N3f4 80. Rh6+ Nfg6

# Answer
> 1 votes
The article mentions:

> Square h8 also being impossible is the result of incredibly complex considerations (Goldsteen spent a month and a half on this problem; 'Not much, for me') that would be beyond the scope of even this article.

There's no obvious reason why h8 doesn't work; a complete proof could even require more characters than fit in a Stack Exchange answer.

---
Tags: problems, knights, retrograde-analysis
---


title: Annotations to Fischer vs Sherwin,1957

text:
# Question
Title: Annotations to Fischer vs Sherwin,1957
I have a Russian translation of Bobby Fischer's My 60 Memorable Games. In the Game 1 (http://www.chessgames.com/perl/chessgame?gid=1008366) in the annotations given after Black's `4. ...Ng8-f6` the author writes that `4...d5 5. Nbd2 Bd6 6. Bg2 Nge7 7. 0-0 0-0 8. Nh4!`

```
[fen ""]
1. e4 c5 2. Nf3 e6 3. d3 Nc6 4. g3 d5 5. Nbd2 Bd6 6. Bg2 Nge7 7. O-O O-O 8. Nh4

```

results in White's initiative. I think that `initiative` means creating direct threats to which the opponent must respond immediately. But where is initiative after `Nh4`? White doesn't seem to create any direct threats at all

# Answer
You are correct; there is no initiative. The author is overstating the idea behind Nh4 which is to throw pieces and pawns toward the black king, who is at this point in no danger.

If you put this in a modern chess program it would probably show the position as completely equal.
> 1 votes

---
Tags: terminology
---


title: Problems: record for most mates-in-2

text:
# Question
Title: Problems: record for most mates-in-2
Does anyone know what the record for most mates-in-2 is for a composed problem?

Example: this one has 58 different moves that mate in 2.

```
[FEN "6R1/8/8/8/3Q3B/5K2/7k/1R6 w - - 0 1"]

```

# Answer
Sir Jeremy Morse, in *Chess Problems: Tasks and Records*, Introduction, cites this construction by E. Luukonen:

```
[Title "E. Luukonen, Uusi Suomi, 1936"]
[fen "kr6/pnPPPPPPPP/P2N4/R7/3BBN2/1Q6/3K3P/6R1 w - - 0 1"]
[StartFlipped "0"]

```

All of White's 117 moves lead to mate in 2. White has no mate in 1, but if Black's rook were to move, or if (after White captures that rook) Black's king were to recapture, White then has a mate. Thus a waiting-move is enough.
> 18 votes

# Answer
I assume you want positions where a mate in one is not possible. Also, these kind of records are often two-fold: one with promoted pieces and one without.

Here is such a position with 76 different mate in twos. I don't think this is anywhere near a record though.

```
[FEN "8/PPPPPP2/3N2pQ/6Rp/3B2p1/1B4Pk/R6P/4N2K w - - 0 0"]

```

The main idea is to play a waiting move; Black's only move is h4 after which Qxh4 is mate. This works for all 24 promotions, 10 knight moves, 18 bishop moves, 11 moves by the rook on a2, Kg1, Rxg6, Qh7 and Qh8. On 1. Nf3 and 1. Nf5 Black can respond by taking the knight, but Be6 resp. Qxh5 mates. The moves Rga5, Rb5, Rc5, Rd5, Re5 can also be met with a black g5 (and Rf5 by gxf5), but Qxh5 is mate then. 1. Rxh5 gxh5 2. Qxh5 is mate (also in reverse order). Finally, 1. Rxg4 Kxg4 2. Be6 is also mate.
> 3 votes

# Answer
When promoted pieces are allowed, William Shinkman has the record with **216 mates in two.** I came across it in the Die Schwalbe Chess Problem Database.

```
[Title "William A. Shinkmam After S. Hiatt, Brownson's Chess Journal 1886, Mate In 2"]
[FEN "1Q5R/4Q1K1/B1Q5/B4Q2/N2Q4/pQ4Q1/pn2Q3/krQ4R w - - 0 1"]

```

Another category to be considered is no promoted pieces with no promotions allowed. Here is my try with a count of **93 mates in two.**

```
[Title "me, chess.stackexchange.com 2/24/2020, Mate In 2"]
[FEN "R7/2R5/8/1K3BBN/3Q4/1P6/4N1pp/5nrk w - - 0 1"]

```
> 1 votes

---
Tags: checkmate, problems, records
---


# Question
Title: Studying why Gardner's Minichess Variant is solved?
I recently came across an interesting article that proves Gardner's Minichess is solved (2013) and the theoretical result is a draw.

Might studying why Minichess is a theoretical draw help me better understand the concepts behind long term strategy in standard chess?

Here is the starting position of Minichess:

# Answer
This variant is definitely very interesting, and could prove somewhat beneficial in learning standard chess.

However,

* Standard Chess(SC)'s castling operation is not reflected in this variant. Your king is already tucked away.
* This variant does not reflect SC pawn structures. Space is too limited.
* The value of pieces changes. Knights are going to be worth more than in SC, since they can now traverse half the diagonal of the board in two moves.
* No opening knowledge whatsoever will be attained in this variant. Also, common opening motifs from SC (control the center, develop your pieces) will not be used.
* Standard tactics from SC will not be used as much in this variant. Skewers and pins, for example, would be quite rare.

That leaves endgame practice, which could be a little helpful, but there's also endgame puzzles in SC - and actual SC endgames in SC.

> **Conclusion:**

If your goal is to further your understanding of standard chess, you are better off studying standard chess. This variant looks like a lot of fun, but it does not do a good job of teaching typical chess lessons, for reasons outlined above.
> 4 votes

# Answer
In my experience, small variants emphasize tactics and not so much strategy. This is due to:

1. the closer proximity of all the pieces
2. the reduced board-size cramping pieces and exacerbating their deficiencies.

My conclusion is thus that **studying small variants does not help with strategy**, but can help with tactics.
> 4 votes

---
Tags: strategy, chess-variants
---


# Question
Title: Setting DGT North American clock for two time controls
Does anyone know how to set a blue DGT North American chess clock to the time control of:

2 hours for the first 40 moves, with 30 minutes added thereafter, with 10 second delay throughout the course of the game?

I found the following information here (http://www.amazon.com/DGT-North-American-Chess-Clock/dp/B00312D2OU) and hope that it is false:

> Most disappointing to me is that, though it claims to have all major North American time controls, it is missing an important one. The time control 40 moves in 2 hours + 1 hour
> thereafter WITH a 5 second DELAY. This is fairly common (at least in Texas) to have a
> delay on the control, but this clock does not do the move counter (i.e. automatically add time after the fortieth move) with a delay. It will do it with an INCREMENT, but not a
> delay.

# Answer
You can *almost* do what you're describing with this clock.

In actuality, it is better to NOT add time after move 40, but instead add the extra hour after one side's clock runs to 0:00. This is because it is fairly common for the wrong side to start (i.e. time would be added after black's 39th move) or for the clock to be pressed an extra time which would result in time being added after white's 39th move. This is problematic because now the clock says that you have, for example, 61 minutes left when in reality you would only have a minute to make your move.

So with that intro, it is very easy to setup the clock with two time controls and a 10 second delay. As described above, the extra hour is added after the time first goes to 0:00. A small flag icon is displayed and the clock continues counting down from 59:59.

In order to set the clock this way, you would use preset 23. (Turn the clock off then back on and press the + button or - button until 23 is displayed)

After selecting preset 23, set the main time for the first time control to 2:00:00 on the first screen. Then the clock will display `1 | 0.00` with the word "delay" in small print underneath the time. This is the delay for the first time control. Set this to `0.10` for a 10 second delay.

Now simply repeat these steps for the second (and possibly third) time control and you're ready to play.

One last caveat, before you start the game (by pressing the play/pause button), make sure that white's side of the clock is raised by pressing black's side. Most clocks can be started by simply pressing black's clock at the start of the game, but this clock needs to be unpaused in order to begin.
> 1 votes

# Answer
The DGT North American and DGT 2010 were designed for different markets. DGT's assumption was that one style of clock delay/increment would prevail in the US, and that's what the NA is equipped with. The other is what prevails in other countries, which is what the DGT 2010 uses. They are otherwise identical.

FYI: The DGT 3000 (a newer and more expensive model) offers both types of delay/increment mechanism.
> 0 votes

# Answer
As the new owner of a DGT 3000 I am disappointed to inform you that it is only capable of Fisher delay (increment type) for any time control with a set number of moves like 40/2 hours followed by whatever. There is no way for it to do a US or Bronstein delay for a given number of moves.
> 0 votes

---
Tags: time-control
---


# Question
Title: What are the pairing regulations for a single-elimination (knockout) tournament?
Here are the pairings for the 2017 FIDE World Cup. The above pairings are for 128-player knockouts. I can't get the way the pairings were generated. I want to be able to generate pairings using the same criteria for knockouts with different numbers of players.

Are there any FIDE published rules for single-elimination tournaments, such as the World Cup? If not, what are the criteria they use for such pairings?

*As it stands, there are no , or tags. I couldn't find appropriate tags, so feel free to re-tag this question.*

# Answer
The participants were seeded by their FIDE rating: the highest rated player (Magnus Carlsen, 2822) got #1; Wesley So, rated 2810, got #2, all the way down to Oluwafemi Balogun (2255), seed #128.

In the first round, the player with number *x* plays against the opponent with number *129 - x*. So 1 vs. 128, 2 vs. 127, and so on.

In the second round, assuming the stronger player (with the lower number) advances, the player with number *x* plays against the opponent with number *65 - x*. So 1 vs. 64 (this actually happened) and 9 vs. 56 (but this became 9 vs. 73 since 73 beat 56).

The 'target sum' for the third round is 33, for the fourth round 17, and so on until the final where #1 is supposed to play against #2.

This all is a standard seeding mechanism used in many sports (sometimes with slight variations); actually, in most cases, only the top n% (25% is common) of the players is seeded and the rest are paired randomly. This tournament was 'completely' seeded, which is relatively rare.
> 4 votes

---
Tags: tournament
---


# Question
Title: What is this opening/position called, and what is white’s best move?
```
 [FEN "r1bqk2r/pppp1ppp/2n2n2/2b3B1/4P3/8/PPP2PPP/RN1QKBNR w KQkq - 0 1"]

```

Do you know the name of this opening/position? Additionally, please tell me what white’s best move is in this position. I ask this because I play aggressively, and I need help with finding my next best move.

# Answer
> 4 votes
It looks like you arrived at this position with the moves

```
[FEN ""]
[StartPly "10"]

1. e4 e5 2. d4 exd4 3. Qxd4 Nc6 4. Qd1 Nf6 5. Bg5 Bc5

```

White is already worse here because you're behind in development. There's no reason to have your queen chased around like that; therefore, it sees very little play and the position does not have a name. If you want to play aggressively, play 3. c3 instead (the Danish Gambit), and there are plenty of aggressive options after 2. Nf3 as well. This question lists more options you might be interested in.

Right now, you should concentrate on completing your development, e.g. with 6. Nc3. Playing aggressive moves in this very position will for sure lead to a quick defeat.

---
Tags: opening, analysis
---


# Question
Title: How to play vs. 1.e4 e5 2.Nf3 Nc6 3.Bc4 d6?
As title above, how to play vs.

```
[fen ""]

1.e4 e5 2.Nf3 Nc6 3.Bc4 d6

```

I see that this move (3...d6) is generally considered inferior in books, or not even mentioned in books about 3.Bc4, but I cannot see a clear way to obtain advantage.

# Answer
> 9 votes
The game will get the characteristics of the Philidor Defense rather than the Italian Game. Wikipedia calls it the Semi-Italian Opening.

> I. A. Horowitz called the defence "solid", also writing: "It does not seem quite sufficient for equality."

The Wikipedia article notes several possible continuations for White, with 4. d4 probably the best bet for advantage.

# Answer
> 9 votes
1.e4 e5 2.Nf3 Nc6 3.Bc4 d6:

365chess.com database shows:

```
MOVE   | games | year |  White +  Draw  + Black
-------+-------+------+--------+--------+-------
4. d4  |  491  | 2018 | 50.3 % | 24.4 % | 25.3 %
4. c3  |  359  | 2018 | 53.5 % | 20.6 % | 25.9 %
4. d3  |  357  | 2018 | 45.4 % | 22.7 % | 31.9 %
4. h3  |  323  | 2016 | 42.7 % | 25.7 % | 31.6 %
4. Nc3 |  289  | 2018 | 50.9 % | 16.3 % | 32.9 %
4. O-O |  249  | 2019 | 50.6 % | 22.1 % | 27.3 %

```

White will get a space advantage and freer development after d4 (whether delayed or played immediately). Or White can play the pawn to d3 and the fact that his Bishop is outside the pawn chain (and Blacks Bf8 is inside) gives White an easier position.

There is no knock-out blow for White as Black is accepting a slightly passive but solid position.

# Answer
> 3 votes
There is no way to "crush" that move. You just play! Develop your pieces, get space in the center and obtain a small advantage. Your opponent won't be losing a piece or something like that.

I assume 3...d6 may have some ideas related to a pin on g4 (for instance, 4.d4 Bg4) A c3 pawn advance can be useful to prevent some ...Nd4. I think you'll be fine after 4.0-0 Bg4 5.c3, but also 4.Nc3 Bg4 5.h3 or many other sequences

In short, I don't know what the best answer is. I doubt anyone in the world actually does. Analyze your games and find what works best for yourself

---
Tags: opening, 1.e4, italian-game, open-games
---


# Question
Title: How to use ending evaluation in UCI interaction with Stockfish
Playing around with the Stockfish 8 UCI from the terminal, I've managed to make it compute moves, and set the position and load Syzygy tables.

But how I can know if an endgame, one that corresponds to the kind of endgame I've loaded, is winnable or drawable?

I've looked at the Stockfish UCI protocol, but I have not found the relevant information.

# Answer
> 1 votes
If the root position you set up on the board is covered by the syzygy tablebases you loaded, you can just directly query the tablebases using the Stockfish-specific (non-UCI) command `d`, see the example below.

Since syzygy tablebases are depth-to-zero (DTZ) and not depth-to-mate (DTM) (see https://www.chessprogramming.org/Endgame\_Tablebases#Metrics for the definitions), what you get is the result with perfect play for the side to move as well as the number of half moves until the 50 move rule counter will be reset due to a capture or pawn move.

input:

```
setoption name SyzygyPath value {path to your tablebases}
position fen 8/8/8/5k2/8/1R6/R7/4K3 w - - 0 1
d

```

output:

```
info string Found 35 tablebases

 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   | k |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   | R |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 | R |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   | K |   |   |   |
 +---+---+---+---+---+---+---+---+

Fen: 8/8/8/5k2/8/1R6/R7/4K3 w - - 0 1
Key: 48F90DF481A6F1D6
Checkers:
Tablebases WDL:  Win (Success)
Tablebases DTZ:    7 (Success)

```

---
Tags: endgame, stockfish, tablebases, uci
---


title: Is AlphaZero deterministic?

text:
# Question
Title: Is AlphaZero deterministic?
AlphaZero searches for moves using Monte Carlo Tree Search (MCTS). As I understand MCTS, it takes the root position, goes to a child node, and then plays random moves until one side wins. Since the moves played are random, does that mean AlphaZero is also random?

Related: this question shows that Stockfish and other conventional engines are indeed deterministic if one looks only at the number of nodes evaluated. I don't know however if the same applies to AlphaZero.

# Answer
> 2 votes
No. MCTS is generally not deterministic. However, it's not that bad given how powerful Google's machines were.

# Answer
> 1 votes
It seems Alphazero is deterministic, up to a point. Looking at the details of its implementation, there's nothing inherently random in it. If one looks at the TCEC bookless bonus between Leela (an Alphazero clone) against Stockfish, this particular Leela net always played the same opening move 1.e4 when it was white. Against this Stockfish sometimes played 1...e6 and sometimes 1...c5; Leela always responded with the Steinitz Boleslavsky variation and Najdorf English attack respectively. In fact, almost every time it's Stockfish deviating instead of Leela:

> Leela is more stubborn than Stockfish in its opening moves. All the major opening classes in the first few moves - Sicilian, French, Ruy Lopez, Italian, QGD - were determined by Stockfish either in black or in white. Stockfish expanded the opening tree almost every move in at least one opening line, again in both white and black. Leela, on the other hand, almost always played the same move when presented with the same position. In the first 24 plys of 100 games I found only 3 cases where Leela expanded the opening tree, on move 7 as black in QGD (game 29), on move 10 as black in Ruy Lopez (games 45 vs 97), and on move 10 as white in French (game 84).

Although Leela was a lot less random than Stockfish, it wasn't completely deterministic either, presumably because of multithreading & random fluctuations causing a different number of nodes to be evaluated. Take out these factors, and Leela (and hence Alphazero) is deterministic.

---
Tags: engines, alphazero
---


# Question
Title: Is it racist that white pieces move first in a chess game?
There is a movement in chess endorsed by several grandmasters called “MoveForEquality”, which revolves around the idea that the black pieces should start first instead of the white pieces. The movement made me feel that white moving first is morally wrong and is somehow discriminatory on race. Is it racist that white moves first? If not, then why does the movement “MoveForEquality” exist?

# Answer
> 12 votes
No, it's not racist; it's just a convention. Or like the famous chess saying goes: "White begins, Black wins". There are other board games like Go where Black begins, or games where it depends on which variation you play.

The main problem with changing who moves first (or alternating it) is that many diagrams which have been printed (especially in opening books) would be invalidated, or at least require extra brain processing (mirroring) to make them work.

Personally, I'd rather have chess players focus on giving people from underdeveloped countries more chances to participate at the international level than something (trivial IMHO) like this. But it's a (mostly) free world and everybody may devote their energy as they deem fit, as long as it doesn't harm others.

# Answer
> 7 votes
> Is it racist that white moves first?

No. According to MoveForEquality.com:

> The rule was originally developed to make annotation easier, and has never been considered in the context of prejudice.

The goal of this movement was never to permanently change the rules of chess. The reversal of the rule for who goes first was simply a way "to inspire a worldwide discussion about equality" on the International Day for the Elimination of Racial Discrimination, which was March 21.

---
Tags: opening, rules, super-grandmaster
---


# Question
Title: Which chess courses should I start with?
I know the rules and played with my friends but without any knowledge of opening tactics etc. And all material I could find online was not in an ordered manner . So can you suggest some courses I can enroll myself online which cover the basics going all the way to the advanced level ?( I am an absolute beginner)

P.S.: Free resources would be more appreciable because I am just a student . Thanks

# Answer
> 1 votes
The Elo rating system is quite simple in an essence, and functions as such: By beating a higher rated player, you accumulate more Elo rating points than if you were to beat a lower rated player. (Elo rating points basically measure your chess aptitude).

As for the other aspects that you have mentioned, I would recommend that you visit chess.com and lichess.com.

---
Tags: beginner
---


# Question
Title: Does the Chronos GX have a count up setting?
I've had the Chronos GX for a while now. However, I don't use it much anymore because I need a count up setting. In other words, I'd like it to start at 0 and have it count up as time is spent.

The regular Chronos has the `UP-1` and `UP-2` settings. The GX seems to lack those. Or am I missing something?

The GX user manual doesn’t give me much hope.

# Answer
> 3 votes
It appears that the Chronus GX clock does not have a count up mode.

While the normal one does, as you have mentioned, it seems that the GX doesn’t. I found this video on how to set up a count on the normal one. It cites pages 35-36 of the manual on how to do this. As expected, the online PDF of the manual corresponds to the video’s given information.

My conclusion is that if the GX manual does not contain information on how to do it, then it cannot do it. Further evidence of this from this video on how to use GX clock. As far as I can tell, it has no mention of a count up setting.

So unfortunately the Chronus GX Clock has no count up setting as far as I can tell.

---
Tags: chess-clocks
---


# Question
Title: How many chess players are over 2500 Elo?
They say that there are currently about 1500 grandmasters. I was wondering how many chess players currently have "grandmaster strength".

# Answer
The website 2700chess.com has a database with the FIDE ratings (from May 1st, 2019). Their search form only offers the option to show the top 50 or 100 players satisfying the search results, but it's possible to modify the submit request and ask for the top 5000 instead. When I do that, I get **808** results:

So the other 700 must have ratings lower than 2500 or have stopped playing competitive chess altogether.
> 35 votes

# Answer
Using the official FIDE rating lists, there are 954 players with above 2500 ELO. Currently, FIDE has awarded 1668 players the title of "Grandmaster". Filtering out inactive players, there are 1334 GMs and 729 players with "grandmaster strength".

There are GMs with a current ELO as low as 2138.

Keep in mind that titles can be awarded for achieving certain placements at tournaments (direct titles) and that the ELO of a player may vary considerably over time.
> 12 votes

---
Tags: rating, grandmaster
---