# Question
Title: How would you determine that the player is cheating in online chess?
There are a lot of online websites, where players can play chess in real time with each other. Most of the games are 5-10 minutes long. With the availability of chess software one can take an advantage by using Fritz or Rybka to suggest a move for him.

For instance, I can just enter every move of my opponent and see what software will suggest for me.

I was thinking about a few features which can suggest that the player is cheating:

* number of times he switches the screen
* speed of play (in easy and in really hard positions)
* accuracy of the game

Does anyone have any other ideas?

P.S.: It does not matter for me, which perspective you are thinking from (server or the client side).

# Answer
> 44 votes
This is actually a very complex question, and not one which has been solved in a satisfying way, to my knowledge. Essentially, we're asking for an algorithm to perform a kind of reverse Turing-test, to differentiate between human players and computers.

First, client-side checks will always have weaknesses, unless you are in *complete* control of the client environment. Let's take the first idea - checking for switching between windows, it sounds good. Unfortunately, it's trivially worked around by running a chess engine on a separate computer, or integrating my engine with the client so that no "window switching" takes place, or changing the client to report 0 changes in window, or... There's no real way to be sure that it's *your* code running on the client, really.

What we're left with is physically tightly controlled client environments (which isn't going to happen for any online games), or server-side checking, i.e. looking at the actual moves that were played (and perhaps the time between the moves, as you say), and trying to deduce the computer or human aspect.

Server-side checking can also split a couple of ways. You could probably try a "top-down" approach, which would be something along the lines of "from past games in history, only 2% of humans made that move, while 50% of computers make it". This would actually be a pretty good way to do it, if we had enough data for "any given position". The search space of chess is so large, however, that even very large data sets will not have a significant number of games matching your position, once you get past the early mid-game.

Assuming that we don't have any reliable statistics on the human side of the equation, you could still present the position to a number of chess engines (with a number of different time settings each), and see how closely the players' moves match that of a computer. By itself, this would also lead to many false-positives, however, repeated positives for the same chess engine and time settings would make it more and more probable that the player was cheating. To further enhance this, I would probably look into a "bottom-up" approach of analysing chess positions; in short, trying to figure out why humans and computers play differently. E.g. humans tend to recognise common patterns. In a game with "odd" patterns, or unlikely situations, a human would be less likely to be able to play very accurately. None of these, by itself, are particularly damning, but given large numbers of games, it would highlight trends to administrators.

To add a few specifics to your list, I would go along the lines of how professors detect plagarism in papers - by detecting a sudden change. In chess, this is extremely difficult to define, but a sudden change in play style or play strength may indicate cheating. Specifically, I'd look for uncharacteristically aggressive moves which tend to just "work out", and have no downside for the player (too accurate). Forced mates in 4+ moves from a player who normally puts knights on the edge of the board, etc (it's possible... just not likely). How exactly this would work sounds like it could take up an entire book (or more), however.

EDIT: There was an article about cheating and detection in top-level chess recently.

# Answer
> 25 votes
In blitz, you can tell by how much time they're using. People using engines use a consistent amount of time for every move, instead of blitzing through the opening and slowing down to a crawl in the middlegame like most normal players. In particular, they can't play the opening fast, because they have to update their computer board after every opening move. If they take five seconds on move two and five seconds on move twenty, they're probably using an engine.

# Answer
> 17 votes
Number of screen switches and speed of play are meaningless. If you use these to complain to the organizers of an online chess playing website they will laugh at you.

There are two ways to tell if someone is cheating. The first is the "smoking gun". Consider this game section -

```
[White "Allwermann,Clemens (1900) "]
[Black "Kalinitschev,Sergey (2505) Boeblingen (9), 30.12.1999"]
[FEN "r6k/1p3Rpp/p2p1bq1/3N4/2P5/1P6/P1b2QPP/5RK1 w - - 0 1"]

1.Qa7 Rg8 2.Qxb7 Be4 3.Nf4 Qf5 4.Qd7 Qe5 5.Kh1 g5 6.Nh3 g4 7.Nf2 Bf5 8.Nxg4 Be4 9. R7xf6 Bxg2+ 10. Kxg2 Qe4+ 11. Kh3

```

The question is what would you play in the that position? The situation is that a win in this, the last round of the competition, will win you the tournament ahead of a string of grandmasters. Not bad for a mere 1900. I suspect most of us would play something reasonably solid which keeps the win. Moves like Rxb7 or Rd7 or (for cowards like me ;-) Rxf6. Qa7 is a heart-stopper of a move, a smoking gun. Fritz rates as the best move in the position, a whopping 0.1 ahead of the next best move, Rd7.

Smoking gun #2 game at the end of the game when black resigned leaving the 1900 rated player as the tournament outright winner. What would you say to Kalinitschev in that position?

This is how the conversation went:

Allwermann: "It's mate in 8"

Kalinitschev: "I don't think so"

Allwermann: "“Check it out, you'll find I'm right"

Allwermann was right, of course. Can you find the mate in 8 in the final position? Without silicon assistance?

So, you have your smoking gun and you take it to the organizers. What will they do?

Well, then comes the second way of detecting and proving beyond reasonable doubt that cheating is going on.

They will need to collect at least 20 games each with at least 20 non-database moves and feed them into an engine for checking. Basically what they are looking for is the percentage of the time the suspect chooses a non-database move which matches the engine's first pick, one of first 2 picks, one of first 3 picks. The "proof" thresholds are -

Top 1 65%

Top 2 80%

Top 3 90%

A recent example is the furore over the performance of Borislav Ivanov.

Here are his statistics -

Zadar 19th: Houdini 1.5a x64 Hash:256 Time:30s Max Depth:20ply { Borislav Ivanov (Games: 9) }

{ Top 1 Match: 210/314 ( 66.9% ) Opponents: 150/313 ( 47.9% )

{ Top 2 Match: 270/314 ( 86.0% ) Opponents: 207/313 ( 66.1% )

{ Top 3 Match: 285/314 ( 90.8% ) Opponents: 238/313 ( 76.0% )

{ Top 4 Match: 293/314 ( 93.3% ) Opponents: 267/313 ( 85.3% )

In the 8th round the live feed went down (it is suspected that this allowed his outside help get the moves) and he lost to GM Predojevic. If this result is removed then the new statistics are:

Zadar 19th: Houdini 1.5a x64 Hash:256 Time:30s Max Depth:20ply { Borislav Ivanov (Games: ) }

{ Top 1 Match: 197/287 ( 68.6% ) Opponents: 135/286 ( 47.2% )

{ Top 2 Match: 252/287 ( 87.8% ) Opponents: 188/286 ( 65.7% )

{ Top 3 Match: 265/287 ( 92.3% ) Opponents: 218/286 ( 76.2% )

{ Top 4 Match: 272/287 ( 94.8% ) Opponents: 242/286 ( 84.6% )

As you see, both sets of statistics would get him thrown of a chess server. For comparison here is the analysis for game 8 when the feed was down:

{ White: Borislav Ivanov }

{ Top 1 Match: 13/27 ( 48.1% )

{ Top 2 Match: 18/27 ( 66.7% )

{ Top 3 Match: 20/27 ( 74.1% )

{ Top 4 Match: 22/27 ( 81.5% )

{ Black: Borki Predojevic }

{ Top 1 Match: 15/27 ( 55.6% )

{ Top 2 Match: 19/27 ( 70.4% )

{ Top 3 Match: 20/27 ( 74.1% )

{ Top 4 Match: 25/27 ( 92.6% )

Note that FIDE has set up a commission to investigate ways to detect and combat computer cheating. Their guidelines are here. Note this section:

> E. The FIDE Internet-Based Game Screening Tool
>
> FIDE will supply an Internet-based Game Screening Tool, which will be accessible to all authorized FIDE officials (IO, IA, ACC members) and National Federations . It shall be hosted on a FIDE-dedicated webpage and will enable authorized parties to upload games in PGN format for a “fast test” that will identify potential outliers in a tournament . By “screening” it is understood that this provides only a preliminary test with no judgment value, except that it may be cited while rejecting allegations and declining to proceed to a manual full test .

# Answer
> 9 votes
To give my answer as to how I would approach this, I would use a simple idea:

* **Null Hypothesis Test**

The idea is that there are is a limited number of publicly available chess engines, lets say `N` of them. This assumption of course precludes the possibility that the cheater has written their own chess engine (or is using some publicly unavailable chess engine) but for catching casual cheaters this should be a strong enough assumption.

The application of the **Null Hypothesis Test** would be very simple: for each chess engine `X` and for each subsequence of moves of the current game compute the probability `p` of observing the played subsequence *assuming* the **null hypothesis** that the player is **not** using chess engine `X` to make the moves for them. A naive assumption could be made that the player moves at random (or randomly chooses from a select number of top moves `d_i`), then the probability for a given subsequence of length `k` matching moves a chess engine `X` would make would be computed as `(d_1)/(n_1) * (d_2)/(n_2) * (d_3)/(n_3) *...* (d_k)/(n_k)` where `d_i` is the number of possible (top) moves to make at the `ith` turn, as rated by engine `X` and `n_i` is the number of total moves available to the player at turn `i` (or some reasonable subset.)

Then simply compute

```
p* = minimum p over all chess engine X, all subsequences y.

```

If `p*` is less than a certain threshold label the player as a cheater since there exists a subsequence `y` and chess engine `X` that brings the probability that the player is **not** cheating below a desired probabiity.

# Answer
> 8 votes
If your site give the users one-click get FEN positions or PGN *while the game is running*, you should consider tracking these.

Some cheaters cheat from the beginning, but others prefer to only start cheating when they are in trouble, and they will obviously use the copy FEN/PGN feature since it is time-consuming to set up the position manually.

You should somehow store that along with the move at the time he copied it, this way you can compare from that point to the following moves and see if his strength greatly increased with the aid of chess engines.

But it is very important that you use it only to help you decide if he was cheating, it would be unfair to use a script that uses no human intervention, there can be many false-positives, for example, I often like to copy positions while I am playing to later analyze them without the need of searching for my game or finding the exact move from the PGN. And I don't always leave it in my clip-board because fear of overwriting it so I move it to notepad (which means I switch windows just after copying it).

# Answer
> 8 votes
I think post-game analysis gives you the best chance of identifying if a player was cheating. This can be done using what is called as the T3/T4 analysis.

This basically measures the frequency at which a player picks one of the top 3 or top 4 moves that are suggested by an engine. This largely eliminates the need to identify the target engine in use (as they will generally agree on the top 4/5 moves even if the order of preference is different).

There are software available that will run a set of games of the user against the top n moves of the engine. Edit:

I am aware of ChessAnalyse that can be used to do such an analysis. You can try the 30 day trial version.

# Answer
> 3 votes
FWIW, no one has mentioned Dr. Ken Regan by name, though the pointer to Lipton's blog describes *another article* in *Chess Life* that discusses his work.

That article is very informative about Regan's work, the state of detection techniques that were in effect in 2014, and FIDE's work in setting up a committee to define and promulgate standards, tools and techniques to assist TD's in stamping out cheating.

# Answer
> 1 votes
I added my views to http://talkchess.com/forum3/viewtopic.php?f=2&t=78146. It has some general outline.

---
Tags: analysis, online-chess, cheating
---


# Question
Title: A suggestive opposite color Bishop ending
The following position appeared to drive even modern engines crazy!

```
[FEN "8/8/b1kP2p1/P5P1/8/BK6/8/8 b - - 0 1"]

```

BLACK to move will get the following results: Komodo 24.1 64-bit depth 61= 3.46 Stockfish 14 depth 54= 1.12 Stockfish 6 depth =81 1.97 I ask the following position to be passed on TalkChess.com to see whathappens with perfect play.

# Answer
Here is an attempt to justify "Draw". What should be the plans for White? Obviously wander with the king to...

* Force entry to f6. This would win by zugzwang after some manouvering (play B to c7 and K to f7, the bB gets "scissored").
* Force entry to c7. The d pawn queens (or the a).
* Force entry to b8. The a pawn queens.

Unfortunately for White, the board is a line too short on either side. Black's correct plan for defense is playing the K to e6 immediately and the B to the long diagonal. Then, always block an eventual Kd4 with Ke6, Kb6 with Kd7 and Ka7 with Kc8. Laugh about the a-pawn running to a7, the B will control a8.
> 3 votes

---
Tags: analysis
---


title: Reanalyzing old chess books

text:
# Question
Title: Reanalyzing old chess books
Computers were demolishing analyses *way* before they became God (see e.g. here), but latest at ELO 3000 or so it became humiliating. Do you know instances of chess books explicitly rewritten years later by the same author, this time with computer-analysis aid? Preferably with the author telling the amount of errors found.

# Answer
> 7 votes
> Do you know instances of chess books explicitly rewritten years later by the same author, this time with computer-analysis aid? Preferably with the author telling the amount of errors found.

No. This doesn't happen. Why would it? There is nothing to be gained by this.

What does happen with a few old books with good reputations that were written using descriptive notation is that a new edition is brought out with computer checking and corrections and translation into algebraic notation. The algebraic notation is probably a bigger selling point than the computer checking.

Of the authors who make a point of using extensive computer checking GM Dr John Nunn comes the closest to doing what you seem to want but for individual games rather than whole books.

He has written an excellent book with the slightly misleading title "*John Nunn's Chess Course*". It seems to really be an examination of some of Emanuel Lasker's games with a more marketable title, but maybe I'm just being cynical.

A big part of what he does in the book is tear apart the analyses of various annotators, reasonably modern so as not to be too unfair, and name and shame.

In chapter 2 "*Misunderstood Genius*" he analyses two previously analysed Lasker games. At the start of the second he says:

> This time the references are to *Why Lasker Matters* by Soltis (Batsford 2005) and *Emanuel Lasker Games 1904-1940* by Soloviov (Chess Stars 1998).

After a short hatchet job he concludes:

> This example provides an interesting case study. The games of the great historical masters are often treated poorly by modern annotators, but rarely does one see such an extreme case. It's not just a matter of an occasional incorrect move in the analysis, as anybody can make such slips, rather it's a consistent and profound misassessment of the position throughout a large part of the game. Soltis and Soloviov both evaluated equal positions as much better or even winning for Black, while when they thought it was equal, White was actually winning.

He goes on:

> Annotators often seem to have a particular narrative in their minds (often dictated by the consensus view of previous annotators) and believe that at a certain point White is better and at another point Black is better. Then the analysis is twisted to fit the narrative rather then the other way round.

---
Tags: engines, analysis
---


title: How to use my queen better

text:
# Question
Title: How to use my queen better
In many of my games, I'm having problems with developing my queen. I'm aware of basic principles such as not moving the queen too early, or developing it after the minor pieces and so on. Yet, I wonder what else comes after these principles. In general, I'm looking for some practical advice on developing and using my queen better. I'm ~1900 in rapid and ~1700 in blitz on lichess if that matters.

# Answer
Because the Queen is so versatile, it is hard to give general rules, but you might try asking the question, which of my other pieces do I want her to cooperate with? She might combine with one of your Bishops to attack squares of that color, or with Rook(s) to control an open file. Queen and Knight can be deadly together because neither is restricted to one color. Queens are great at shepherding passed Pawns. Paradoxically, you might ask whether there is a task to be done that none of the others can achieve? In all cases, the key is to think about her in relation to your other pieces.

And take a look at Soltis' *Reassessing the Chess Pieces*
> 3 votes

---
Tags: queens, development
---


title: Does learning chess make you smarter?

text:
# Question
Title: Does learning chess make you smarter?
I noticed that a lot of chess experts state or imply that teaching kids to play chess is good for them. I wonder if there have been any reliable studies of this (As in, randomized controlled trials)? I wouldn't be at all surprised if chess-playing kids had higher IQs, but would there be any causation behind this correlation?

# Answer
I believe so. From my personal experience, I found learning chess helped me to concentrate on something for a longer time. It also helped me with my memory specially when it comes to recognizing a pattern. Surprisingly I found chess to be helpful for my math skills, like I can calculate 3-4 lines earlier before I have reached that line while solving a math which I guess the benefit you get from practicing chess calculation. And most of all chess enables me to think clearly for solving any problem,. I believe all these qualities are components of a smart person. But that's also true that it can't be taken for granted.
> 1 votes

# Answer
This is somewhat of a tricky one because this answer is No , Yes and Maybe.

Chess doesn't necessarily make you smarter and there is significant research on the topic. The most clinical being "Your Move: Thee effect of chess on mathematics test scored"

They found that there was an improvement in mathematic scores when one in four weekly mathematic lessons were based on chess learning material.

The theorized reason behind this is due to training of of abilities in reasoning allowing for transference of concepts towards mathematical principals.

Other studies on the topic all generally concluded similar results.

That chess DOESN'T necessarily make you smarter.

I don't believe that chess in of itself makes you inherently smarter. It does however help develop and reinforce skills in Fluid Reasoning, Memory, Problem Solving and Processing Speed. These skills are often used as a determination of cognitive ability / intelligence.

In summary playing chess doesn't make you smarter. It does however re-enforce the required skills for cognitive processing which is often utilized as a measure of intelligence. Training your Brain.
> 1 votes

# Answer
I believe that there are studies coming to both positive and negative conclusions. I suspect that it depends strongly on the manner of teaching. A child who has merely been taught the moves and is able to play a legally correct game may not have have gained very much in other areas, but if the teacher is skilled (at chess and at teaching) then almost any game of chess is full of "teachable moments" in great variety. Although not every child may be equally responsive the possibilities are endless.
> 0 votes

---
Tags: learning, psychology, teaching, children
---


# Question
Title: List of records for the youngest FIDE masters since 1950?
**Edit** based on answer given by blunderchess1236 awhile ago: I'm not looking for just 1 person like who most recently attained the youngest (Alekhine Nouri). I'm asking also who held the record for youngest before Alekhine Nouri and who held the record before that person and so on until the 1st FM/s. (or alternatively start with the 1st FM/s

---

On Wiki, we have the List of youngest grandmasters since 1950. What about the list but for FMs (FIDE masters) instead of GMs? How might I go about obtaining this list?

**Way 1 - start from most recent**: It appears Philippine player Alekhine Nouri is on this list. Here's a source, but it doesn't say who the previous youngest was. If I knew who was the youngest before Nouri, then I could search the 1 before that 1 and so on.

**Way 2 - start from the 1st FM/s**: Who was/were the 1st FM/s? When I look this up, I mostly find just the 1st FMs of certain countries. eg Gerald Mphungu - malawi, Ricko Depaune - Nauru, Peter Wong - Australia but for composition. It seems so weird that this information isn't readily available. It seems to be the case as well for candidate masters: When was the FIDE title of Candidate Master first awarded?

**Note 1**: It appears Susan Polgar may be on this list at the age of 12 or 13.

**Update 2**: It seems Étienne Bacrot (who holds a youngest GM record) is on the list for youngest FM records.

# Answer
"From Wikipedia, the free encyclopedia Alekhine Nouri (born December 12, 2005) is a Filipino FIDE Master. Named after Russian chess player Alexander Alekhine, Nouri became the youngest Filipino FIDE Master and the youngest FIDE Master in the world at the age of 7."

It seems like this person is who you are looking for.
> 1 votes

---
Tags: history, statistics, records, titles
---


# Question
Title: Why does this game not end as a draw by insufficient material?
I played an online game at chess.com and here is the endgame:

```
 [fen "8/8/1p2p2k/pP2P1p1/P1K3P1/8/8/8 b - - 0 1"]

```

After white's last move a4, I thought the game ends immediately as a *draw by insufficient material* as checkmate is theoretically impossible. However, the game lasted 50 more moves before it ended as a *draw by 50 moves*.

My questions:

1. Why does this game not end immediately as a *draw by insufficient material*?
2. As the game continues, is it possible that one side can win by timeout when he/she cannot theoretically checkmate? If this were a game without time increment and each player has only a few seconds, it will just be a competition of who can click the mouse faster and has faster ping.

# Answer
> 12 votes
> Why this game does not end immediately as a draw by insufficient material?

Two reasons.

1. There is no rule regarding ‘insufficient material’. What there is is a draw due to a ‘dead position’. This is defined in article 5.2.2 of the FIDE Laws of Chess:

> 5.2.2 The game is drawn when a position has arisen in which neither player can checkmate the opponent’s king with any series of legal moves. The game is said to end in a ‘dead position’. This immediately ends the game, provided that the move producing the position was in accordance with Article 3 and Articles 4.2 – 4.7.

2. The game was not played over-the-board in a properly run tournament with a qualified arbiter. If it had you could have stopped the clocks and called the arbiter and claimed your draw. The arbiter would then have checked that the last move was a legal one before declaring the game drawn.

As it was played at Chess.com, you should really address your question to the platform concerned. These platforms are businesses and decisions as to what to implement are business decisions. Clearly in this case they decided that the benefit wasn't worth the cost. If you want to try and change this then you need to complain to them.

> As the game continues, is it possible that one side can win by timeout when he/she cannot theoretically checkmate?

Not in a real game in a proper OTB tournament. Online anything is possible.

# Answer
> 5 votes
A bit late, but Miguel Ambrona recently developed an algorithm to assess whether a given position is a draw, or loss on timeout, under FIDE rules—in short, whether a checkmate is at all possible. https://github.com/miguel-ambrona/D3-Chess

He wrote a complete version which finds the correct answer on all positions, at the cost of unpredictable computation time, and a faster version which provides a conservative answer that is correct on nearly all realistic positions (only failing to assess a handful of games out of nearly a billion).

There seems to be some interest in incorporating his code into Lichess: https://github.com/ornicar/lila/issues/9249. If done, this would make the adjucation on that site in line with FIDE rules, though it's unclear whether the computational cost of checking whether the position is a technical draw after every move is worth it. Given his fast and nearly perfect code takes only 3 microseconds on average to run, a good balance might be to check every ply using that algorithm, and check the *final* position using the complete checker. In any case, I think it's fascinating that such a performant algorithm can even be devised that works well on typical "pathological" positions like yours!

---
Tags: online-chess, draw, time-control, dead-position
---


# Question
Title: Why can white not mate in this position?
In the attached position, why can't white mate? Is it not possible to go Rxc6 and depending on blacks response go Rxc6.

```
[FEN "4r1k1/1p3ppp/2b5/5n2/pp6/8/P4PPP/2R1R1K1 w - - 0 1"]

```

Source: Bobby Fischer Teaches Chess (1966) - Bobby Fischer & Stuart Margulies

# Answer
If White goes for 1. Rxc6??, Black has 1...Rxe1#
> 17 votes

# Answer
Based of your question it appears that you have correctly assessed and identified the critical piece holding blacks position together. The Bishop on c6.

**Rxc6 - Removing the Defender.**

```
[FEN "4r1k1/1p3ppp/2b5/5n2/pp6/8/P4PPP/2R1R1K1 w - - 0 1"]

1. Rxc6 Rxe1#

```

Results in a completely lost position which allows black to mate in one.

**Rxe8 - "Correct" Variation.**

```
[FEN "4r1k1/1p3ppp/2b5/5n2/pp6/8/P4PPP/2R1R1K1 w - - 0 1"]

1. Rxe8 Bxe8 Rb1 b5 Rxb4

```

Doesn't significantly change much. Black has a promotion threat on the a/b file. The rook is unable to defend because any attempts to dislodge the bishop will result in either loss of material or promotion. In addition to this the knight has the ability to apply pressure on whites rook.

Engine Evaluations would indicator that white is down approximately 5 pawns (or a rook) of material from the starting position.
> 7 votes

---
Tags: checkmate, fischer
---


# Question
Title: How can one know where two diagonal lines meet?
Is there an algebraic way to know In which square two diagonals meet?

For example a2 and f3 meet in d5

How can one find d5 without looking at the board? (Blindfolded chess exercise)

# Answer
> 9 votes
The math formula is relatively easy (intersection of two straight lines, even with fixed slant), but I assure you I can visualize it much faster on the board than solving it, even if I'm a lousy visualizer!

* Replace the letters with numbers: 12 / 63 \ (These are x,y coordinates)
* 12 is the upward diagonal (you didn't specify but it's obvious)
* Since it is upward, its equation is y-x=2-1
* 63 is the downward diagonal
* Since it is downward, its equation is y+x=6+3
* Solve it in your head (add/subtract to eliminate)
* Solution is x=4, y=5
* Revert x to letter: The answer is "d5"

# Answer
> 12 votes
Actually the accepted answer is not correct. Where do the diagonals from a4 and g4 intersect? There are two solutions, d7 and d1. It is easy to modify @Hauke Reddmann's algebra, but it seems to me much easier (and more useful) to try and improve your visualization.

# Answer
> 6 votes
As many others have pointed out, the best idea is to learn to visualise the board better.

But since there *is* a neat mathematical answer, let's start by converting the letter coordinates to numbers, with A=1, B=2 etc. Then:

(TL;DR:) *Take the **sum** of coordinates of one square, and the **difference** of coordinates of the other, and find the square that matches both.*

Just in case that seems a bit too terse:

There are two diagonals through every square. One of these diagonals preserves the sum of the coordinates, the other preserves the difference.

So, to find the squares reachable diagonally from both a2 and f3, you first convert them into coordinate number pairs:

* a2 = (1,2)
* f3 = (6,3)

and then into sum-difference pairs:

* a2 = (1,2) -\> (sum 3, difference -1)
* f3 = (6,3) -\> (sum 9, difference 3)

Since you have to take a diagonal in a different direction (and thus, preserve a different quantity) from each square, you get the intersection points by taking the coordinate sum of one square, and the coordinate difference of the other. In this case, they are

* intersection 1 = (sum 3, difference 3)
* intersection 2 = (sum 9, difference -1)

You can then convert these back to coordinate pairs and then regular coordinates by a little mental arithmetic:

* intersection 1 = (sum 3, difference 3) -\> (3,0) = off board
* intersection 2 = (sum 9, difference -1) -\> (4,5) = **d5**

And that right there is the answer.

This all looks a lot more difficult than it actually is, because in the real world, we wouldn't try to find both intersections at once, like we did above. Instead we'd just calculate

* *"a2 adds up to 3, f3 has difference 3, so we need (3,0), oops, that's off board"*

and then

* *"f3 adds up to 9, a2 has difference -1, so we need (4,5), ok, that's d5"*.

Special cases: If you ended up with an intersection point that has an odd sum and an even difference (or vice versa), your original squares were of different colours, and of course there is no integer solution to the last step.

Also, if you got the same coordinate sum (or the same coordinate difference) for both of the squares, then the process will give you the two original squares as the result. This means your two squares were on the same diagonal already.

PS. In case you're wondering how one might come up with this kind of idea, this process is actually just a coordinate system switch. We start with the regular orthogonal coordinates, then switch to defining the location each square by the two diagonals it's on. In this coordinate system the original problem is really easy to solve, and then we convert the result(s) back to normal coordinates again.

# Answer
> 2 votes
Sum letter and digit, using A=1, B=2, ...

* A2: 1+2 = 3
* F3: 6+3 = 9

The difference is 6. It is even, so intersections exist.
Half of the difference is 3. That is the delta.

To find the 2 intersections:

* A2 has smaller sum =\> add 3 (the delta) to A and to 2. A+3, 2+3 = D5.
* F3 has larger sum =\> subtract 3 from F and 3. F-3, 3-3 = C0.
In that case it is outside of the board.

A special case is when both squares share a diagonal. You can detect that case when the sums are equal or when interections you find match the original squares. If not, you are good.

# Answer
> 0 votes
**X = (x1 + x2 + y2 - y1)/2** and **Y = X + y1 - x1** Using this formula, we can calculate intersecting square of any two squares on chess board.

for example: a2 \> (1, 2) and f3 \> (6, 3) \[assuming x co-ordinate a =1, b=2, c=3....f=6, g=7, h=8\]

**Note: You should always consider the left side point (square) as to be the first point** So, X = (1+6+3-2)/2 = (10-2)/2 = 8/2 = 4 and Y = 4+2-1 = 5 As, **X=4** and **Y=5** The intersecting square is **d5**

Another thing to mention is that, if you don't get a positive integer (whole number, not fractions) as the X value, it means these two square doesn't intersect at all. That will happen only when you take two different colored squares.

# Answer
> 0 votes
First step: check if both squares are white or black, Write a2 as (1,2), then 1 + 2 is odd hence a2 is white Write f3 as (6,3), then 6 + 3 is odd hence f3 is white

Now, the squares on the diagonal (1,2) are the squares with a difference of 1 (a, a + 1) (and in more general the upright diagonal from (a,b) are those with difference |b-a|. For the squares on the diagonals (6,3), these are the upright squares with a difference of 3 (we can clearly ignore these) *or* the going upleft we subtract from the first coordinate and add to the second.

This quickly gives (6,3) --\> (5,4) --\> (4,5)! bingo! Or even faster, note that their sum, 9, stays the same for an upleft diagonal! Hence we need (a, a+1) with a + a + 1 = 9.

More generally, the upright or downleft diagonals will be easy (some set difference) and the upleft or downright diagonals has a constant sum.

---
Tags: blindfold-chess
---


title: Rook vs Bishop endgame

text:
# Question
Title: Rook vs Bishop endgame
In the following endgame position, from Dautov vs Heinemann, from the book FUNDAMENTAL CHESS ENDING, what happens with perfect play?

```
[FEN "R7/5pkp/4b1p1/3p4/8/5P2/5KPP/8 b - - 0 1"]

```

The book says black has some difficult problems to solve (but does not clarify whether they win), while a Stockfish 11 analysis at a depth of 54 plies returns +2.52, which is promising for white. What's going on?

# Answer
> 1 votes
This position is typical of those that give computers great difficulty because they must be analysed backwards. White will try (somehow) to gain space and penetrate mostly on the dark squares, while placing his Pawns "to maximum advantage" and looking for an opportunity to sacrifice the exchange. In twenty to thirty moves time. If he is lucky (!) there will be some combinational play that increases his advantage.

The problem is that you cannot arrive at this by analysing to 54 ply. At move 1 you have to conceptualize what the winning idea will be, and play toward it. Otherwise, an evaluation based on general principles (as it must be because there are no immediate tactics) may be optimistic but will not get you there. The situation can be summed up with fair accuracy by saying that the computer does not analyse to depth 54, but instead to depth 1, 54 times and this is not at all the same thing.

A strong human player would deal with this by making moves that "look good" while avoiding for as long as possible decisions that cannot be reversed. They would hope that while doing this, any final play that exists might slowly come into focus. If this position had arisen in a world championship match, I think that decades might be spent trying to arrive at a verdict.

---
Tags: analysis, endgame
---


title: Timed Games and improving play?

text:
# Question
Title: Timed Games and improving play?
I'm more of a chess hobbyist, but I'm trying to learn more about the game. I've been working on playing some basic openings. I usually play on chess.com.

1. What's a better timed game to learn from? I usually play 10 minute games, but I've considered switching to 30 minute games until I get better.
2. I keep making a lot of the same mistakes, and I'll readily admit I likely have very, very poor strategy. Any tips on improving there?
3. Is there a way (or a website or something) that I can put in the moves after a game (the PGN) and find out **why** a move was marked as it was (good, excellent, blunder, etc.)?

I know a subscription to the site is cheap, but I don't feel that I'm good enough yet (and don't quite have enough time with all other things I'm doing) to get a subscription.

# Answer
This is a little bit of a tricky question to answer definitively. There are Right and Wrong approaches, there are multiple opinions on what is the best method. I am going to try and approach this somewhat neutrally with my thoughts based of your statements.

***1. What's a better timed game to learn from? I usually play 10 minute games, but I've considered switching to 30 minute games until I get better.***

There are two camps here. Those who say faster games as it helps with pattern recognition. There are those who say longer time controls so you can train analysis and depth. Each camp is right in their own way. Pattern recognition is important, bullet and blitz time controls are quite good at developing that. Rapid games are good analysis. Daily Games are extremely analytical...possibly too much so.

Based of your response that your making a lot of the same mistakes. I think pattern recognition might be a bit of an issue for you at this time. I would actually be suggesting you look into doing Tactics puzzles for 10 to 15 minutes before you play a game with a longer time control say 10 to 15 minutes again. Playing bullet games which rely heavily on pattern recognition when you haven't developed that skill sufficiently is just not a productive endeavour.

***2. I keep making a lot of the same mistakes, and I'll readily admit I likely have very, very poor strategy. Any tips on improving there?***

If you know what the mistakes you are making , such as hanging pieces, you can use the chess.com puzzle functionality and if you click on customise then you will see themes. Select the themes for which you are commonly making mistakes on and set the ratings to be between your current rating and maybe 500 above. Spend time on the positions. Its ok to spend an hour on a puzzle. You are far better to spend time analysing the position getting it right than spending 30 seconds and going "I don't know..." and just moving to progress.

Strategy is very different to train than Tactics and is really about the analysis of the "long" game. Reviewing the board , developing a plan and executing it. The following article provides a reasonable overview. Main thing to remember though is to have a plan...but not to get to attached to that plan.

***3. Is there a way (or a website or something) that I can put in the moves after a game (the PGN) and find out why a move was marked as it was (good, excellent, blunder, etc.)?***

As you are using Chess.com I would actually suggest using the in built analysis tool.

You will notice there is notation after the best suggested move. This is how the engine would interpret the position to be developed if played "correctly". You can even click on the magnify glass to copy the line to the overall game annotation as a variation

In regards to seeing *why* the move is better or a blunder it is a matter of reading or playing out the variation. Adding it to the analysis allows for it to actually be played out as a variation.

I would suggest reading the following article from chess.com though as its quite comprehensive.

If you are willing to make an investment in your learning you could look into applications like DecodeChess which is a reasonably good platform and on the extreme end Chessbase which is a desktop application (extremely pricy though).

**Recommendations:**

I personally prescribe to the longer time intervals for my students as I believe that the process of Analysis significantly improves player skill. Pattern recognition is also extremely important which is why there is also the Tactical Analysis (Puzzles)

This is a very simplified stripped back approach but generally all good training should be balanced between effort,rest and available time.

Rapid 15 Minute games - 5 to 10 games / week

* Analysis of each game Blitz 5 Minute games - 0 to 5 games / week
* Analysis of each game Tactics Puzzles - 10 puzzles a day (exc Rest Days).

One to Two days of the week you don't touch anything chess related.

This sort of format I find generally works well for players between beginner to 1500 range. Focus on maybe learning 3 to 4 openings, the most popular ones focus on the first 4 to 5 moves. This will help set you up.

There are commercial sites like AimChess.com as well provide training programs and generally work on a similar principal. Which I also generally recommend.
> 6 votes

# Answer
In addition to the other answer, I can recommend Lichess, it's totally free and has really nice features. After a game finishes, you can request evaluations. If you click "Learn from your mistakes", you get the positions where you made mistakes/blunders and you try to find the correct move. If you cannot find it, it tells you the correct move.
> 8 votes

# Answer
**1.** I'd advice you to just play the time control you enjoy the most. Ideally, slower games let you think more carefully about your moves so they're great training, but time is a limited resource and you can only play so many 30 minute games.

**2.** This depends on the type of mistake you're making. If you're blundering your pieces away, then you probably need to improve your pattern recognition and calculation skills. Puzzles are great for that (it's like playing a real game where all positions are "critical"). 15 minutes a day of puzzle solving (at full focus, with no solving-by-guessing) should be enough for some improvement to appear after a few weeks.

But it could also be that you're making other types of mistakes. For example, "weird-looking" moves because you reach positions where you just "don't know what to do". If that's the case, then try learning some basic strategical concepts. Seeing some examples of your games where you make those mistakes would be really helpful to the answerers.

**3.** Yes: the human brain. If you want your analysis to help you improve at the game, you need to do it first by yourself and only then (if at all) check your conclusions with an engine. After all, it (hopefully) won't be there to help you in the next game, so doing the effort to figure out why you lost your queen will do more for your game than an app saying "Oh! You lost your queen here. That's bad. Don't do that".... You already know losing your queen is bad!
> 5 votes

# Answer
I dont think that you will improve unless you play SOME slow games. Others have mentioned the resources for learning from them. Then play whatever number of fast games gives you most enjoyment. Unless you are having fun there may be no motive to improve. Analyse the fast games only if are not sure what went wrong.
> 0 votes

---
Tags: strategy, game-length
---


# Question
Title: For those who play the Catalan Opening, what are typical responses to the KID and slav defense?
I'm trying to form a 1d4 repertoire (exculsively 1e4 player) around the Catalan Opening. What are some lines that Catalan players play against the KID and slav defense(it seems the normal catalan setup isn't very effective against the slav?). I know this is an open question but I do want lines in the spirit of the Catalan if possible. Thanks.

# Answer
> 1 votes
This is the exact situation where I found myself and I decided to employ the following move order/repertoire to keep me in the spirit of the Catalan.

* ## King's Indian defence

Against the King's Indian Defence you can use the fianchetto variation (which requires studying the Panno variations from the black side), which is actually quite solid and positional.

```
[fen ""]

1.d4 Nf6 2.c4 g6 3.Nf3 Bg7 4.g3 d6 5.Bg2 0-0 6.0-0 Nc6

```

The above can be met in many different ways: there are 7.h3 lines, 7.Nc3, 7.Qc2 and so forth (you should dig into a little theory here). Notice that 3.Nf3 avoids forcing Grünfeld lines that could occur after 3.Nc3 (3...d5 4.cxd5 Nxd5 5.e4 Nxc3 bxc3 6.c5) because there is in fact no Knight on c3 to be exchanged after 5.e4. The fianchetto variation moreover avoids the automatic plan by Black in the standard variations of the King's Indian (Mar de la Plata) with f5-f4-g5-g4, as the construction with g3-Bg2 by White makes it really hard to sac-sac-checkmate the King.

* ## Slav

To be honest the best way to meet the Slav is to play the main line, as it gives White always a slight edge and if well played Black must defend (though it is by all means very robust and solid for the second player). Here it is important to go 3.Nf3 instead of 3.Nc3 to avoid the Winawer gambit 3...e5 (well, unless you want to play against it and feel comfortable).

```
[fen ""]

1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 dxc4 5.a4 Bf5 6.e3 e6 7. Bxc4

```

and the standard plan is to play Qe2 and then e4-e5 (at the right moment) followed by Bd3 and attack on the Black King. There are fianchetto lines against the Slav as well, however, if you really feel the need to play fianchetto all the times.

# Answer
> 0 votes
If you have a preferred line against the Slav, it can still be compatible with the Catalan. You can go 1.d4 d5 2. c4 c6 and now play whatever you want. It could be 1.d4 Nf6 2.c4 c6 3.Nf3 and play your favourite system.

Against the King's Indian, there are a bunch or interesting fianchetto lines

# Answer
> 0 votes
If you go on amazon and search "Grandmaster Repertoire Avrukh" you will see:

* Grandmaster Repertoire 1: 1.d4 Volume One (v. 1)
* Grandmaster Repertoire 2: 1.d4 Volume Two
* Grandmaster Repertoire 1A - 1. d4 - The Catalan
* 1.d4: King’s Indian & Grunfeld (Grandmaster Repertoire)
* Grandmaster Repertoire 17: The Classical Slav

and more.
GM Avrukh has created the repertoire you seek as a starting point to 1.d4.

He recommends the fianchetto lines against the King's Indian Defense as g3 is a Catalan move after all. Having said that you don't really get any advantage with it! You do get a solid position which you can play chess with.

I too tried to adopt 1.d4 though exclusively 1.e4 forever. I ended up adopting the English first and found some cool anti-slav lines and used the Botvinnik setup against the King's Indian. But again against the Kings Indian I don't see an edge for White -- just a battle.

# Answer
> 0 votes
I have been using the KIA move order 1.Nf3 d5 2.g3 c6 3.Bg2 Nf6 4.OO Bf5 5.c4 against the Slav. Usually I play 6.Qb3 attacking the b7 pawn and play continues from there. White keeps a very small advantage but if you keep attacking on the Q-side good things often happen similar to the Catalan. That is the idea of these openings, to play a low risk variations with long term pressure.

An excellent source for this is Grand Master Repertoire 4, the English Opening, Volume 2, by Mihail Marin. Lots and lots of great information. 10 chapters dedicated to anti-Slav lines.

About the KID I like the book Wojo's Weapons 2 which has very good coverage of the fianchetto lines against the KID. This only comes in paperback so you cannot get an e-book.

---
Tags: opening
---


# Question
Title: Where to find Tactical Exercises on the Decoy
A decoy tactic is forcing an enemy piece to move to a square that prevents it from guarding an original square.

For example, if the black queen is at c7 and the f7 square is being attacked, getting the queen to move to c6 would be a successful decoy tactic.

Where can I find such puzzles?

# Answer
> 1 votes
The paid version of chesstempo allows you to search the problem database for all kinds of tactical motifs. Depending on your exact definition of "decoy tactic", you should look for what they call "attraction", "distraction", "clearance", "coercion", "sacrifice" and perhaps more.

# Answer
> 0 votes
https://www.amazon.com/365-Ways-Checkmate-Joe-Gallagher/dp/1901983951

It has lots of mind blowing tactics inside, including decoys. I finished it in one year and it caused an huge leap in my tactical ability.

# Answer
> 0 votes
Here's a very good one. Make sure you pause the video when you are prompted to do so. Try to find the decoy tactic yourself: https://youtu.be/Ib05HINpMsI

---
Tags: tactics, problems
---


title: Chess visualization exercises

text:
# Question
Title: Chess visualization exercises
As beginner chess player I need an advice from more expert players.

After one month I will partecipate to an OTB tournament and I want to improve my skills doing tactic exercises.

Is it useful to do the tactics on a real chess board or it really doesnt't matter and I can do the tactics visualizing a chessboard on a computer screen?

I don't have too much time to dedicate to the preparation, every tactic exercise takes some time to prepare the real board, so, if the benefit is not evident, maybe in the same amount of time I can do more tactics in front of a computer.

What do you think about?

# Answer
> 1 votes
When working on tactics I like to make a distinction between working on improving visualization and improving pattern recognition. For me, when I'm working on pattern recognition I work on problems that are simple (combinations that are 1, 2 or 3 moves - mostly forced lines) and I use the computer or a tactics app. I expect to be able to solve these problems in less than a minute. Trying to solve as many problems as possible in the given time.

I've found however that using a physical board helps me with visualization training. I use much harder problems here: Problems that would take me 5 minutes or more to solve.

# Answer
> 2 votes
Yusupov is very clear in his books that all the positions should be set up on a board. I often find that problems I'm unable to solve in a book/on a screen are solvable once I've set them up on a board. Also, many trainers/coaches state you should replay games on a board, rather than clicking through them on a site.

---
Tags: tactics, visualization
---


# Question
Title: Why do people say you can't mate with just a bishop?
I mean, looks pretty checkmate to me.

Everywhere I look this up, they never speak about the fact that it is at least theoretically possible to win with just a bishop and a king. Why is that? I mean shouldn't they at least mention it?

Same goes for knight and pawn:

# Answer
> 8 votes
You have correctly stated that one can certainly mate with a single bishop or a single knight when the other side has some pieces on the board besides a king. Your diagrams for sample mates under these conditions look to be correct.

What people are usually saying:

> It is impossible to deliver a mate with only a bishop and king (K+B).

It is **implied**, that **the other side has only a lone king**, no other pieces.

So, a more correct way to express the same thought is:

> It is impossible to deliver a mate with only a bishop and king **against a lone king** (K+B **vs K**).

now, the statement is not ambiguous and factually correct.

# Answer
> 2 votes
When people say "you can't win with \[insert material here\]", they are talking about forcing a mate with the aforementioned material. This is a very general statement that excludes combinations that win tactically because of a specific position, being assisted by the opponent, and so on. To be more precise, what they should say is "From the starting position, remove all the pieces from the board except \[insert desired material confrontation here\]. Do not allow the pieces to move further than their third row in the first ten moves. Then \[insert color here\] can't win".

However, such a sentence is much more convoluted than what they are trying to convey. From a pedagogical and pragmatic perspective, a precise statement is rarely useful: Most of the time they just mean that you can't force a mate with \[insert material here\] against a lone king if it is in the middle of the board.

---
Tags: endgame, checkmate
---


# Question
Title: Is a both-sides forced perpetual check possible?
There are lots of positions where one side can force the other into a perpetual check. Is there any position in which there are no legal moves besides continuing the perpetual from both sides? For example, let’s say White is checking Black. Black has to move due to the check. Then, White somehow has no other legal move than to continue the perpetual.

I am asking purely out of curiosity. I don’t think such a position would be likely to be reached in a real game Ideally, there would only be pieces on the board that are attainable in a real match though, e.g. no 10th queen. I am also interested if it’s possible to prove that there is no such position.

# Answer
Attempt to a partial answer.

I expect this to be impossible, but not by principal means (i.e. a real proof will be very hard and contain many cases), but the limitations of the pieces and the board. To show this, here is a "mild" fairy solution using nothing than a large board and some fancy line figures.

Start with Kc4 Rd5 Rd4 Pd6 Pe5 Pe4 Pd3 - Ka4 Ra6 Ra3 Be6 Be3 Pd7. The intended perpetual is 1.Kc5+ Ka5 2.Ka4+ Kc4. You now "merely" need white girafferiders (a line figure on 1,4-lines) on i2 and i7 to pin the bishops, and four more fancy riders to pin the girafferiders in both positions of the white king.

This setup also shows where the problem is: Why shall White's checking piece not move to the last position of the black king in the next White move? Either because White is in check (but then indeed we run into the problem of a mutual perpetual check, as outlined in my comments) or because it is pinned. But then, why shall the pinner not capture instead? It must be pinned too. And that pinner is White again and must not move either, i.e. must be pinned, leading to some setup like Kh1 Rf3 Bb1 - Kf5 Be4 Ra1. There are only very few of these setups, and worse, since it must be an infinite cycle on a finite board, all moves must ultimately be "taken back", so the Rf3 here must be unpinned somewhen again. How?
> 4 votes

---
Tags: check, forced-move, perpetual
---


# Question
Title: How good is 1. e4 c5 move for black? Why does Stockfish play it?
I've been running some engine vs engine games out of boredom and noticed Stockfish, when playing as black, 90% of the time played c7-c5 on white's e4. I've never actually seen a human play this, in the few years of my playing. Is it a move that mostly professionals play? Is there a concrete reason for that move?

# Answer
> 7 votes
1...c5 initiates the Sicilian Defense. It is absolutely a respectable opening, and I am surprised you've never seen it before. I'll just quote Wikipedia:

> The Sicilian is the most popular and best-scoring response to White's first move 1.e4. Opening 1.d4 is a statistically more successful opening for White because of the high success rate of the Sicilian defence against 1.e4. *New In Chess* stated in its 2000 Yearbook that of the games in its database, White scored 56.1% in 296,200 games beginning 1.d4, but 54.1% in 349,855 games beginning 1.e4, mainly because the Sicilian held White to a 52.3% score in 145,996 games.

Because the Sicilian is so good, it shouldn't be surprising that Stockfish plays the opening.

# Answer
> 3 votes
Any answer to the question will be as dangerously biased as the database behind it, and moreover Stockfish will have other opening "reasons" than a human (I play 100% c5, and that even without knowing theory...), but here are some values from the database behind the Lichess analysis board, as number of games and white win-white loss:

* c5 - Sicilian - 480000 - 6%
* e5 - Open - 230000 - 10%
* e6 - French - 130000 - 11%
* c6 - Caro-Kann - 79000 - 8%
* d6 - Modern - 40000 - 12%
* g6 - probably KID - 30000 - 7%
* d5 - Scandinavian - 22000 - 14%
* Nf6 - Aljechin - 20000 - 11%

Observe how good g6 scores, I guess because it mostly ends as Kings Indian and a no holds barred fight will ensue.

# Answer
> 2 votes
***1...c5*** is a great move that fights for the center even better perhaps than ***1...e5***. By playing ...c5, White will only be able to play d4 either by trading one of his central pawns for a side pawn or by preparing it with c3 (a move the b1 knight won't be happy about).

On the other hand, ***1...c5*** is not a developping move (and does not help development at all), so White can try to profit from an early lead in piece activity. The most ambitious plays to try to exploit that often lead to chaotic games with wild attacks.

Overall, the Sicilian Defense (1.e4 c5) is the most common response to 1.e4 in tournament play. Even if opening popularity is a matter of fashion, the Sicilian has stayed on top for a long time.

---
Tags: opening, engines, stockfish, sicilian-defense
---


# Question
Title: List of records for youngest WCMs (woman candidate masters) since 1950?
**Re the close**: If it was really a duplicate then why didn't Brian Towers♦ answer on the other post? Checkmate!

---

On Wiki, we have the List of youngest grandmasters since 1950. What about WCMs (woman candidate masters) instead of GMs?

---

follow-up questions to brian towers' answer in case they get deleted (I notice that on this stackexchange site, follow up questions or reasons for downvoting can be removed without warning or explanation!):

1. what is this database please? may you please share the database or how it was constructed or something here? chess.stackexchange.com/a/37013 i mean: did you really download all the stuff since 2001 and then combine all the data into 1 huge database? or what? or did you get it from somewhere or what?
2. as for re research effort: it seems the only way to do this is to get the database. so how? really downloading and combining everything? seems pretty long to do. i figured somehow there was something already constructed. if i do this from scratch, then i risk reinventing the wheel. am i wrong?
3. do we have the same 'procedure/algorithm' here chess.stackexchange.com/questions/36988/

---

Youngest CMs: List of records for youngest CMs (candidate masters) since 1950 (or 2014 or whatever)?

Youngest female CMs: List of records for youngest female CMs (candidate masters) since 1950 (or 2014 or whenever)?

Youngest WCMs: List of records for youngest WCMs (woman candidate masters) since 1950?

# Answer
Perhaps worth noting why the question has attracted down votes. If you hover your mouse over the down arrow it starts off by saying :This question does not show any research effort".

It is worth pointing out that one of the best places to start your research is this forum. Searching for questions about candidate master titles gives a number of useful hits.

This question - When was the FIDE title of Candidate Master first awarded? \- has the very useful answer -

> The first rating list that contains the Candidate Master title is April 2002 and all the players on that list with the said title are from England followed by Wales in the next rating list (July 2002)

The CM and WCM titles were created at the same time and so there were no WCM titles anytime before 2002 and certainly not in 1950.

Furthermore the CM and WCM titles are not particularly prestigious. Amongst other ways of getting these titles is by finishing in the first 3 in continental championships for children as young as 7 or 8. Try doing an advanced search on the FIDE rating website for WCM players and you will see players with ratings just above the 1000 threshold. I think this change to the title requirements was made in 2012 so players awarded the title before that were 2000 rated or over.

Searching my database constructed from data available on the FIDE Ratings Download page gives the following results. Note that FIDE gives only the birth year for players due to data privacy laws so age was calculated as 'Year of title' - 'Year of birth' so some of the players marked as 8 years old may have actually been only 7 years old when they won the title.

**Year Name Age Fed**
2002 Haslinger, Mandy S 22 ENG
2003 Wilson, Alexandra 17 ENG
2004 Liu, Yang Hazel 14 SGP
2005 Nguyen, Thi Mai Hung 11 VIE
2005 Phan, Nguyen Mai Chi 11 VIE
2008 Chiang, Sarah 11 USA
2008 Kiseleva, Arina 11 RUS
2009 Ivana Maria, Furtado 10 IND
2012 Salonika, Saina 9 IND
2012 Solozhenkina, Elizaveta 9 RUS
2012 Tran, Vuong Mai Khanh 9 VIE
2013 Ismayil, Malak 9 AZE
2013 Pham, Tran Gia Thu 9 VIE
2019 Bashirli, Saadat 8 AZE
2019 Zhumagali, Raian 8 KAZ
> 4 votes

# Answer
> what is this database please?

The database I use is an SQL Server database I built several years ago using data downloaded from Olimpbase for the years 1967-2001 and the FIDE download page for 2001 to today. Note that while the Olimpbase link I have given is for one zip file containing all the data 1967 to 2001. The FIDE page, however, requires you to select and download each period individually. In the early years after 2001 that was 4 files per year. Later that moved up until for the last few years it is one per month, 12 per year.

This is a massive amount of very dirty data. The current download for September 2021 holds data for 1,025,666 players. My current database comes in at over 15 GB. The idea that you could download it from me is nonsensical.

Regarding research, you have obviously done none. The obvious place to start is this community. Had you done so you would have likely found this similar question - Creating program for finding top players with respect to elo and age \- and with it my answer. The final paragraph of my answer is particularly relevant -

> A major task will be extracting the data you need from your data sources. This will be a massive task. I would suggest you design a relational database for your needs and populate it from your data sources after first cleaning the data. Once this is done answering the questions you want is a relatively straightforward matter of writing some simple database queries and running them.

In summary:

1. Download all the data
2. Identify "dirty data" and clean it
3. Design your database bearing in mind the structure of the raw data and how you want to use that.
4. Load the data into your database.

There is a fifth, ongoing task:

5. Every month download the latest data from FIDE, check it for dirty data (unfortunately there is still some despite my regular complaints to the relevant FIDE officer when I get fed up), clean the dirty data and load it into the database.

On the dirty data, front check out this answer I gave to an earlier question relating how FIDE and the federations abuse FINS. I still haven't gotten over what they did to Tony Miles.
> 3 votes

---
Tags: history, statistics, records, titles, women
---


# Question
Title: Why is ..Kh8 so much worse than ..Kg7 after Nf6?
I just "failed" this Lichess exercise. Main line is Stockfish's, secondary is mine's.

```
[FEN "r5k1/3N1p1p/2p1p1pb/3pP3/p2P3q/5P2/PP2QP1P/R4RK1 b - - 2 19"]

1...Bf4 2. Nf6 Kg7 {-5.4 according to Stockfish} (2...Kh8 {+1.9??} 3. Ng4 Qh3 {why not h5 already?} 4. Rf1d1 h5) 3. Ng4 h5 {Exercise completed successfully}

```

The basic idea was clearly to use the threat of a checkmate on h2 with the bishop and queen, and so I did.

The only option for white then was to check my king with the knight. After that, I figured it didn't really matter where my king escaped to (as long as it was safe), since white's next move would obviously be 3. Ng4 to protect h2 and prevent my mate attempt.

Some time ago I learned that "the safest spot to escape from a knight is two diagonal squares from it", since it'd take said knight at least three moves to get to a position where it can attack the same piece again.
So, to play it safe(r), I decided to go 2...Kh8 ...and that's where I failed!

But why? White's knight is going to g4 anyways and my pawn is going to h5 anyways, so what's the difference?

# Answer
> 33 votes
Excellent question because the difference between these two king moves is actually quite subtle! In general you're completely correct that moving the king two diagonal squares away from it ensures the king will be safe from the knight. However in this position, we know the knight is already headed to g4 to defend h2, so we shouldn't be afraid of the knight at all.

Instead, we should mentally prepare for what's happening after h5, winning the knight. There's two reasons that Kh8 is inferior: one positional and one tactical. After the moves h5 and hxg4 we should now see that taking on h2 with check is actually detrimental to black's king safety because the the h file is newly opened and both the queen and king are on the newly opened h file - positionally not OK. Moreover, there's an amazing tactical sequence that black has that requires the king to be on g7 instead of h8 (covering the h6 square turns out to be decisive!). Let's see how that plays out...

```
[FEN "r5k1/3N1p1p/2p1p1pb/3pP3/p2P3q/5P2/PP2QP1P/R4RK1 b - - 2 19"]

1... Bf4 2. Nf6+ Kg7 (2... Kh8?? 3. Ng4 h5 4. Kg2 hxg4 5. fxg4 Qxh2+ 6. Kf3 Qh3+?? (6...Bh6 {Best play - stopping our own attack just to avoid getting hurt on the newly opened h file. White is winning.}) 7. Kxf4 g5+ 8. Kxg5 Kg7 {Black needs to avoid Rh1 winning black's queen but it's already too late} 9. Rh1 Qg2 10. Rag1 Qe4 11. Qxe4 dxe4 {White is up a rook in the endgame and completely winning with their active king now no longer in danger of any mating nets.}) 3. Ng4 h5 4. Kg2 hxg4 5. fxg4 Qxh2+ 6. Kf3 Qh3+! {The tactical difference is now revealed!} 7. Kxf4 g5+ 8. Kxg5 Qh6#

```

As an aside this is why I don't like tactics from online trainers and much prefer them from books (although chesstempo does a good job of curating their puzzles as well). Engine-created puzzles will simply play the best lines according to the engine instead of playing the most human continuation that requires a critical understanding of the tricks lurking just beneath the surface. Seeing all 8 moves in the main line would be extremely difficult from the starting position, and certainly far above the pay-grade of whatever rating this lichess puzzle is. However, because you can easily "guess" one of the two king moves after which the puzzle immediately ends, most users are missing out on the entire point of the actual puzzle!

# Answer
> 2 votes
This isn't really an answer except to say that the question might be wrong. This appears to be allowed as indicated here. But anyway just in case NoseKnowsAll from here has already given an answer and it seems to be the same as 1 of the analyses I ran just now.

**My opinion: Don't overthink this.** Just downvote the puzzle and move on. I have 2 reasons why

1. Even if the puzzle is correct, it's not necessarily the case that you'll immediately get a human answer when you run the analysis. Therefore, it's much to think for such little gain.
2. Unlike chesstempo, lichess doesn't really have a system for discussing puzzles and voting on different/extra moves. So you might do something like this for chesstempo but for lichess really I think ordinary thinking you might do on chesstempo might be overthinking for lichess. In fact on chesstempo, you might not have to do any thinking because the stronger players have already done it for you. You can possibly get a human answer if you ask on stackex like you did just now, but my opinion is you'll end up doing this a lot. My guess is this will be a huge wheel reinvention for puzzles that have been or will be downvoted a lot anyway. Could be wrong, but 1 way to check is if lichess will show the vote total for the puzzles similar to how chesstempo does.

* Note: I'm not saying chesstempo is superior to lichess in every way. I mean Lord knows I strongly prefer the lichess endgame puzzles over the chesstempo endgame training). It's just that lichess' discussion and vote system is non-existent. (If chesstempo had endgame puzzles and those tags like pawn endgame, queen and rook endgame, etc, then it's bye bye lichess puzzles. I'll even become a paid member of chesstempo if that's what it takes.)

**Btw, if I have to give an answer anyway:**

In another (but probably wrong on my part) analysis I ran it seems with Kh8 like besides putting your king on the h file to be exposed to the rook as pointed out in NoseKnowsAll's answer, you're also putting your king on the 8th rank to block your own rook from coming to the h file for some computer reason that I don't know, didn't bother to know and have no interest of knowing. Like white will still play Ng4, but h5 doesn't work anymore (h5 is also not the best move). And then in the Kg7 line you can play Rh8 where as this is no longer an option in the Kh8 line.

---
Tags: analysis, middlegame
---


title: Jobava vs Milton 2005 Skandemborg game

text:
# Question
Title: Jobava vs Milton 2005 Skandemborg game
In the following position, from the above game, the book ROOK vs Minor pieces endgame give AN almost easy win for White. Yet I tried on my Houdini 6.02 and got a draw instead. The position is WHITE King on d2 Rook on c3 Knight on f3 pawns on a2 b2 e5 f2 g2 h2. BLACK King on f8 Rook on c8 Bishop on c6 pawns on a6 b5 e6 f7 g6 h7. What happens with perfect play? White moves.

# Answer
> 1 votes
**Original Game in Full** Position occurs on blacks move 24 (Bxc6).

```
[Event "Samba Cup"]
[Site "Skanderborg DEN"]
[Date "2005.10.23"]
[EventDate "2005.10.14"]
[Round "9"]
[Result "1-0"]
[White "Baadur Aleksandrovich Jobava"]
[Black "Kamil Miton"]
[ECO "D80"]
[WhiteElo "2601"]
[BlackElo "2636"]
[PlyCount "77"]
[FEN ""]

1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. Bg5 Bg7 5. Bxf6 Bxf6 6. cxd5 c6 7. Rc1 O-O 8. dxc6 Bxd4 9. c7 Bxc3+ 10. Rxc3 Qxd1+ 11. Kxd1 Nc6 12. e4 Bd7 13. Nf3 Rfc8 14. Bb5 Rxc7 15. Kd2 a6 16. Ba4 Rcc8 17. Rhc1 b5 18. Bb3 e6 19. e5 Kf8 20. Bc2 Na5 21. Bd3 Rxc3 22. Rxc3 Nc6 23. Be4 Rc8 24. Bxc6 Bxc6 25. Ke3 Ke7 26. Ng5 h6 27. Ne4 Rc7 28. g4 Kd8 29. Nf6 a5 30. h4 Kc8 31. Ng8 h5 32. gxh5 gxh5 33. Nf6 Kb7 34. Nxh5 b4 35. Rc1 Rd7 36. Nf6 Rd8 37. h5 Bb5 38. Kf4 Rd3 39. Rh1 1-0

```

**Position Analysis**

I ran an analysis of the position using a engine and server configured as such;

* 256 AMD EPYC CLL
* Stockfish 14
* 7 Man Syzygy End Game Table
* Analysis Rate 350MN/s

From the base position Stockfish 14 analysis would indicate that white is winning with +-7.66. I let the engine run for 15 minutes came back and the engine has resolved the position to a mate. The full sequence is below.

```
[Event "Samba Cup"]
[Site "Skanderborg DEN"]
[Date "2005.10.23"]
[EventDate "2005.10.14"]
[Round "9"]
[Result "1-0"]
[White "Baadur Aleksandrovich Jobava"]
[Black "Kamil Miton"]
[SetUp "1"]
[FEN "2r2k2/5p1p/p1bp2p1/1p2P3/8/2R2N2/PP1K1PPP/8 w - - 0 1"]

1. exd6 {256 Core GPU Cluster - Stockfish 14 +NNUE Syzygy 7 Man Table 350 MN/s}  b4 2. Rc4 Ke8 3. Ne5 Bd7 4. Rxb4 f6 5. Nc4 Kd8 6. Kc3 Be6 7. b3 Rc6 8. Rb6 Kd7 9. Rb7+ Kd8 10. Rxh7 Bxc4 11. bxc4 Rxd6 12. h4 Ke8 13. Rg7 f5 14. f3 Kf8 15. Ra7 Re6 16. c5 Ke8 17. a4 Re2 18. Rg7 Rxg2 19. c6 Kd8 20. h5 g5 21. h6 Rh2 22. h7 Rh4 23. Kd3 Kc8 24. a5 Kd8 25. Ke3 Kc8 26. Kf2 Rh2+ 27. Ke1 g4 28. Rg8+ Kc7 29. h8=Q Rxh8 30. Rxh8 Kxc6 31. Rh6+ Kb5 32. Rf6 g3 33. Rxf5+ {End Game Table calculated Calculated Mate} Kb4 34. Rg5 Kc3 35. Rxg3 Kd4 36. Rg6 Kc5 37. f4 Kd5 38. Rxa6 Ke4 39. Rf6 Kd3 40. a6 Kc2 41. a7 Kc3 42. a8=Q Kc4 43. Qc6+ Kb4 44. Qd5 Ka3 45. Rb6 Ka4 46. Qa2# {Max Depth=103}

```

**Thoughts**

* The reason why Houdini gave the position as a draw is due Houdini being somewhat outdated when compared to a lot of the Free and Open Source engines such as lc0 and Stockfish as examples. The way these engines perform Alpha and Beta pruning in comparison to Houdini is prenominal. What this results in is Houdini burning resources exploring a line that algorithmically isn't necessarily the best line.
* Analyzing positions to this level of depth is meaningless. There is no Grandmaster in the world capable of memorizing a end game sequence 90 moves long. In addition to this the effort required to analyze a position to this depth when it has only occurred once. Perfect play isn't a thing even engines can do. It is a close as we currently have but even engines make mistakes.

---
Tags: analysis
---


# Question
Title: Does blitz change the relative value of position vs material?
The way I see it, true gambits trade material for position, which in turn could give you opportunities to regain more material. However, in blitz play, you are less likely to notice those opportunities in order to exploit them. Is it fair to say that blitz changes the relative value of position vs material? In particular, should you prefer to accept (and not offer) gambits more?

# Answer
It just seemed obvious to me that gambits would work better with faster games, for the same reasons as given in the comments - it's harder to defend than attack, etc. I tried looking at several gambits in the lichess database to support this theory.

In classical+rapid games, White wins 53% of Evans Gambit games vs 43% for Black. In bullet+blitz games, it's 51% for White and 46% for Black.

Let's look at the King's Gambit. In classical+rapid games, White wins 53% and Black wins 43%. In bullet+blitz, it's 49% for White and 47% for Black.

Halloween Gambit? Classical+rapid leads to 52% White 43% Black. Bullet+blitz leads to 52% White 44% Black.

Englund Gambit (a gambit for Black) has 49% White 46% Black for classical+rapid, and 50% White 46% Black for bullet+blitz.

As a control I then looked at 1.e4 to make sure this wasn't something that happened in general. 1.e4 had 49% White and 46% Black for both classical+rapid and blitz+bullet, so this isn't simply a general effect of the time control getting faster.

Well then. This kind of busts my theory. It seems the gambiting side has a better record in the slower time controls, and the defending side has a better record in the fast time controls, after all! The effect is, however, small, and probably not worth basing your play on.
> 20 votes

---
Tags: positional-play, evaluation, gambits, blitz, material-balance
---


title: Why is stalemate a draw?

text:
# Question
Title: Why is stalemate a draw?
It is so difficult to force stalemate and sometimes unintentional too, so why is stalemate a draw?

> As the opponent doesn't have a further move, why is it not considered a win?

# Answer
> 43 votes
Stalemate is a draw in classical chess yet there are other chess variants both historical and modern where stalemate is not a draw.

Very early versions of Chess, such as Shatranj Chess (props to Andrew Latham) declare the player causing stalemate the winner and even today there are callings to return to that rule.

for example:

Larry Kaufman Chess Life Sept. 2009 writes:

> "calling stalemate a draw is totally illogical, since it represents the ultimate zugzwang, where any move would get your king taken"

A typical counter to this point is that Chess tradition dictates that a stalemate cannot result in a win for the stalemating player because it would require a suicidal move from the stalemated player (moving your king into check is, in most forms of chess, an illegal move). If there are no moves on the board that you are able to make (other then resigning) then in making the stalemating move your opponent has effectively ended the game without a definitive result (capture of the king) and is judged to have not won the game.

So.. "In Classical Chess what is the probable origin of stalemate being considered a draw?"

The earliest reference I can find to Stalemate being a draw in formalised chess rules is 13th century Italy where the version of Chess played declared that a game could only be won by checkmate or resignation. Stalemate, under those terms, describes a state where a player cannot make a legal move. In effect the game has stalled in a state where neither player can achieve Checkmate and is drawn.

Stalemate as a draw then spread to Germany (1400s), Spain (1600s) and throughout Europe by 19th Century when the formal rules of what we know as classical chess were put in place.

England was one of the final adopters of Stalemate as a draw in the 1800s (up until that point the stalemated player had actually been declared the winner).

Opinion:

Yes tradition does favors the player in stalemate but it has been that way for a very long time. The flipping of that advantage to the stalemating player would greatly change the nature of the endgame (and thus the game of chess and a huge amount of chess theory), which is probably why such arguments have not recieved too much traction.

# Answer
> 28 votes
I think stalemate is a draw for the same reason that dropping the white ball when potting black is a loss in 8-ball pool - it gives the losing player a granule of hope until the very end, and it ensures that the winner must be clinical in securing his win.

With regards to whether this flows logically from the other rules of the game - chess is, after all, a human made game, not a form of mathematics, so a rule does not have to be logically consistent with all other aspects of the game. If we all agree that a specific rule is good for the game, then we don't need to justify this rule against the logic of other rules (en passant and castling are similar).

# Answer
> 25 votes
As Totero notes, changing stalemate in this fashion would drastically change endgame play. Currently, one must learn how to recognize different King/Pawn endings, and how other pieces interact with these endings. Opposite- vs same-color Bishops, Knight/Pawn vs Knight, Rook/Pawn vs Rook, and other basic variations.

Changing stalemate to a win would throw much of that out the window. Who cares whether White or Black has the opposition? Just run that Pawn down the board. Rook/Pawn vs Rook? No worries, just force a trade, and the win is guaranteed. It might not be fair to say that this would trivialize endgame play in reducing it to mindless exchanges from material superiority, but it would be a drastic change.

Put another way, it takes more skill to calculate and remember ending positions than it does to march one's way to a stalemate, and the stalemate rule is intended to recognize that fact.

# Answer
> 12 votes
I remember reading somewhere once which advocated that stalemate should be (could be) 3/4 point. Unfortunately, a quick google search turned up nothing.

The idea is interesting. It seems that you gained more by stalemating your opponent than you gain if the position is completely equal. By similar logic, the stalemated side seems to have not lost as badly as he would have if he had been checkmated.

# Answer
> 10 votes
There would definitely be some logic in considering Stalemate a win (after all, the opponent's King *has* to move and and will be captured on next move, so that *should* be a win).

However, this would have a huge impact on the whole Chess game. The reason is that, if Stalemate wins, now **all** King+pawn VS King endings are winning. Thus being one pawn ahead, exchanging all the pieces leads to a trivial win. I am not saying it would be bad, just that it would change the game more than you imagine.

For more details on the Stalemate (and on the key position in K+P VS K endings), you can have a look at the following blog post I wrote.

# Answer
> 8 votes
Simple reason - you cannot kill the king in his current place and the king is dead if he moves. So they maintain status quo till eternity, meaning stalemate.

# Answer
> 7 votes
The objective of the game is to achieve a checkmate. If you leave your opponent no legal moves, then he/she is not in check, is not checkmated, yet can't move. It speaks to the ability of the player to recognize the possibility of stalemate, and avoid it while playing for the checkmate (or opponent resignation).

You haven't achieved the objective of the game, hence, a draw.

# Answer
> 5 votes
Stalemate is a draw by definition. Why is it a draw? Because this is the rule that was agreed upon in the 19th century. Before the 19th century, the stalemate rule was not standardized. By defining stalemate as a draw, winning has become more difficult. Stalemate is an important resource to hold a draw. For example, many rook endgames are drawn because the defending side sacrifices their rook to create a stalemate. The stalemate also offers escape from clearly lost positions where the opponent loses focus and allows the stalemate to happen. My view is that the stalemate adds flavor to chess.

# Answer
> 2 votes
Big flaw in the classic chess game. The logic thing would be for the stalled player to pass the move back as in other boardgames where you are not able to move. If no player can move, then its a draw.

# Answer
> 2 votes
I thought of a weird line of reasoning for which a stalemate would be considered a *loss* for the attacking player (who causes the stalemate), because at lower levels it is caused by a blunder by the attacker and at higher levels it means the defender has outmaneuvered the attacker to force a stalemate. But it doesn't feel quite right to call it a loss when the attacker is apparently winning, while there should be some reward for a defender cleverly forcing a stalemate. The compromise is to call it a draw, though it comes down to your opinion on how much to reward each player for their play that led to the stalemate.

# Answer
> 0 votes
Lack of moves to do, don't happen only because all your possible moves would lead to you putting yourself in check. It's possible for player X to make a move that create a situation where player Y can't make any moves, even ones that would put themselves in check.

The reason they made stalemate a draw, was probably/maybe to simplify the stalemate rules, instead of being a win if you only have moves that would put you in check, and being a draw if you have no move, they simplified it to make everything a draw.

Making stalemate a loss for the stalemated player would also be wrong, there are situations where you wouldn't have any move to do (including ones that would put you in check) and you would lose.

# Answer
> -1 votes
Because the king is not under attack. Attacks are the single most salient feature of the game of chess. How could you win without an attack? Can you capture material without an attack? Similarly.

---
Tags: history, draw, stalemate
---


title: What is an "ugly" move?

text:
# Question
Title: What is an "ugly" move?
In the video "ugly defense", GM Grigoyan called the move Knight g3-h1 an "ugly move", though objectively speaking, Nh1 may be the best move for white in this position.

```
[fen "r1b2rk1/b1p4p/p1pp1qp1/P7/4P1n1/3N2N1/1PP2PPP/R1BQ1RK1 w - - 1 1"]

```

May I know if there is a definition of an "ugly move"? In my humble opinion, if a move is objectively the best in a particular position, it should be called a "good move", or sometimes a "brilliant move", or sometimes a "forced move", or sometimes a "book move". In this position, I would call Nh1 a "forced move".

# Answer
An "ugly move" is one which violates positional principles. Here the knight on g3 attacks / defends 6 squares - h5, f5, e4, e2, f1 and h1. On h1 it only attacks/ defends 2 squares - g3 and f2. Positionally it is much better on g3 than h1. However tactically f2 is key because it is attacked 4 times, pinned against the king and only defended 3 times. It is a far more important square than all the 6 squares the knight can reach from g3. Although Nh1 is an ugly move it is also a necessary and good move. These terms are not mutually exclusive.
> 25 votes

---
Tags: terminology, chess-videos
---


# Question
Title: List of records for youngest WFMs (woman FIDE masters) since 1950 (or whenever)?
On Wiki, we have the List of youngest grandmasters since 1950. What about WFMs (woman FIDE masters) instead of GMs?

**Note 1**: I really mean to ask about WFMs (females who obtain the female exclusive title WFM) and not female FMs (females who obtain the open title FM).

**Note 2**: WCM was answered here: List of records for youngest WCMs (woman candidate masters) since 1950?

# Answer
> 2 votes
Searching my database constructed from data available on the \[FIDE Ratings Download\]\[2\] page gives the following results. Note that FIDE gives only the birth year for players due to data privacy laws so age was calculated as 'Year of title' - 'Year of birth' so Salimova, Nurgyul may have actually been only 7 years old when she won the title.

**Year Name Age Fed**
1981 Brustman, Agnieszka 19 POL
1984 Olarasu, Iuliana 17 ROU
1985 Maric, Alisa 15 YUG
1988 Polgar, Judit 12 HUN
1990 Stefanova, Antoaneta 11 BUL
2004 Hou, Yifan 10 CHN
2007 Salcedo, Jackeline 9 COL
2011 Salimova, Nurgyul 8 BUL

---
Tags: history, statistics, records, titles, women
---


# Question
Title: List of records for youngest female international masters since 1950?
**Note**: I really mean female IMs and not WIMs

**All IM version**: List of records for youngest international masters since 1950?

**WIM version**: List of records for youngest WIMs (woman international masters) since 1950?

---

On Wiki, we have the List of youngest grandmasters since 1950. What about female IMs instead of GMs?

**Edit 1**: Who was/were even the 1st female international master/s?

**Edit 2**: I guess Judit Polgar is on this list because:

> With these three results, she completed the requirements for the International Master title; at the time, she was the youngest player ever to have achieved this distinction.\[45\] Both Bobby Fischer and Garry Kasparov were 14 when they were awarded the title; Polgár was 12.\[46\] It was during this time that former World Champion Mikhail Tal said Polgár had the potential to win the men's World Championship.\[47\]

# Answer
> 2 votes
> Who was/were even the 1st female international master/s?

As far as I can see from the Olimpbase data (pre 2001 when FIDE started publishing) Judit Polgar was the first at the remarkably early age of 12 in 1988. No female has beaten that record so her name is the only one on the list.

Excluding Judit Polgar still gives a very short list:

**Year Name Age Fed**
(1988 Polgar, Judit 12 HUN)
1992 Xie, Jun 22 CHN
2002 Kosteniuk, Alexandra 18 RUS
2002 Kuharenko, Svetlana 18 UKR
2003 Lahno, Kateryna 14 UKR

The point being that to win the title directly requires the player to win the World Open U16 title or higher so this is not an easy title that is handed to little children with low ratings.

---
Tags: history, statistics, records, titles, women
---


# Question
Title: How many Chess960 positions exist in which castling on one side does not require moving the rook on the other side?
**Update**: It's chess870 (or chess869). See answer.

---

**Context/Motivation/Goal**: In regular chess, you never have to move a rook (on 1 side) to castle (on the other side). My aim is to see how much of 9LX is lost if we retain this. My hope is that it's not much given that it appears to be that usually you don't have to move a rook (on 1 side) to castle (on the other side). This way, you can develop then queen, knights, and bishops without having to give away where you're castling.

**Now for 9LX**: From a not-so-random sample of some of my 9LX games, I notice that, in most positions, if you remove all the pieces besides the kings, rooks, and pawns, then you don't have to move a rook (on 1 side) to castle (on the other side)

Here is an example of not having to move a rook to castle:

```
 [FEN "bqnrkbrn/pppppppp/8/8/8/8/PPPPPPPP/BQNRKBRN w KQkq - 0 1"]

```

Here is an example of having to move a rook to castle. (You have to move the short/h-side rook to castle long/a-side, assuming of course black doesn't interfere like black knight captures rook and then runs away.)

```
 [FEN "rknrbbqn/pppppppp/8/8/8/8/PPPPPPPP/RKNRBBQN w KQkq - 0 1"]

```

**Question**: Restricting ourselves only to positions of the first kind, how many such positions exist?

**Maybe related**:

1. Chess480: Why 480?
2. Which side should I castle if I have opportunity to castle on both sides?
3. Update: This too I guess based on comment: Minimal number of moves before castling in Chess960

**Note**: It appears that separating the rooks by at least 2 squares in between them isn't sufficient based on the 2 examples above. I guess at least 2 squares for the kingside, but at least 3 squares for the queenside.

# Answer
Ah well, I can program that in MATHEMATICA in ten minutes, regardless of the details...

```
L = Permutations[{"K", "Q", "R", "R", "B", "B", "N", "N"}]; (* all permutations *)
T1[LL_] := (Position[LL, "R"] // First // First)
         < (Position[LL, "K"] // First // First)
         < (Position[LL, "R"] // Last // First); (* king between rooks true? *)
T2[LL_] := EvenQ[1 +
           (Position[LL, "B"] // First // First) +
           (Position[LL, "B"] // Last // First)]; (* unequal colored bishops true? *)
LF = Pick[L, (T1[#] && T2[#]) & /@ L]; (* CURRY STYLE YEAH! *)
(LF//Length) == 960 (* True! *)

GR[LL_] := (Position[LL, "K"] // First // First) < 7; (* OO king right *)
GS[LL_] := (Position[LL, "K"] // First // First) == 7; (* OO king stay *)
GL[LL_] := (Position[LL, "K"] // First // First) > 7; (* OO king left *)
CR[LL_] := (Position[LL, "K"] // First // First) < 3; (* OOO king right *)
CS[LL_] := (Position[LL, "K"] // First // First) == 3; (* OOO king stay *)
CL[LL_] := (Position[LL, "K"] // First // First) > 3; (* OOO king left *)
FR[LL_] := (Position[LL, "R"] // Last // First) < 6; (* OO rook right *)
FS[LL_] := (Position[LL, "R"] // Last // First) == 6; (* OO rook stay *)
FL[LL_] := (Position[LL, "R"] // Last // First) > 6; (* OO rook left *)
DR[LL_] := (Position[LL, "R"] // First // First) < 4; (* OOO rook right *)
DS[LL_] := (Position[LL, "R"] // First // First) == 4; (* OOO rook stay *)
DL[LL_] := (Position[LL, "R"] // First // First) > 4; (* OOO rook left *)

(* now counting we go! *)
{Pick[LF, GR[#] & /@ LF] // Length,
 Pick[LF, GS[#] & /@ LF] // Length,
 Pick[LF, GL[#] & /@ LF] // Length,
 Pick[LF, CR[#] & /@ LF] // Length,
 Pick[LF, CS[#] & /@ LF] // Length,
 Pick[LF, CL[#] & /@ LF] // Length,
 Pick[LF, FR[#] & /@ LF] // Length,
 Pick[LF, FS[#] & /@ LF] // Length,
 Pick[LF, FL[#] & /@ LF] // Length,
 Pick[LF, DR[#] & /@ LF] // Length,
 Pick[LF, DS[#] & /@ LF] // Length,
 Pick[LF, DL[#] & /@ LF] // Length}

{852, 108, 0, 108, 168, 684, 174, 174, 612, 786, 102, 72}

```

So you can read off: The "long" rook goes leftwards in 72 cases, stays put in 102 cases and goes rightwards (jumps) in 786 cases. And so on. You can also combine ad libitum:

```
SR[LL_] := (Position[LL, "K"] // First // First) == 6 &&
           (Position[LL, "R"] // Last // First) == 7; (* OO in 1st move! *)
SL[LL_] := (Position[LL, "K"] // First // First) == 4 &&
           (Position[LL, "R"] // First // First) == 3;(* OOO in 1st move! *)
{Pick[LF, SR[#] & /@ LF] // Length,
Pick[LF, SL[#] & /@ LF] // Length}

{90,72}

```

And finally, if the right rook stands in the way of castling left or vice versa, this means

```
PR[LL_] := (Position[LL, "R"] // First // First) >= 6; (* left rook must clear at least f to OO *)
PL[LL_] := (Position[LL, "R"] // Last // First) <= 4; (* right rook must clear at least d to OOO *)
{Pick[LF, PR[#] & /@ LF] // Length,
Pick[LF, PL[#] & /@ LF] // Length}

{18,72}

```

**Conclusion**: This means one rook obstructs castling with the other in **90 cases**.

* (Actually one can do this in the head: on the long side, the right rook has to be at "d" or left to it, giving RKRX,RKXR,RXKR,XRKR, on the short, "f", so only ...XRKR works. Now always one B has 3 and the other 2 spots independently, and on the remaining the Q can be placed on 3 spots. Fill up with N. Altogether thus there are 5x3x2x3=90 positions where you can't castle before moving the other rook away.)
> 6 votes

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Tags: chess-variants, castling, mathematics, chess960
---


# Question
Title: Are there videos of the highly-skilled fast online players (e.g. GM Andrew Tang) showing their mouse skills?
It's impressive watching players like GM Andrew Tang play ultra bullet and puzzle rush at super-fast speeds without it being a complete mess. I'm curious as to how they do it. When I try, I physically can't move fast enough (I tend to do better on a touch screen): I can't envisage how it's possible to move so fast.

**Question**: Are there videos of the highly-skilled fast online players showing their mouse skills?

# Answer
> 2 votes
Yes, there are several.

As stated by @B.Swan, you can search for "Andrew Tang Mouse Speed". Here are a couple videos that come up.
https://www.youtube.com/watch?v=tGvgXH\_SQtU
https://www.youtube.com/watch?v=EwP2nFbYm5c
https://www.youtube.com/watch?v=4nSyv0IY6gg

Another GM that comes to mind is Daniel Naroditsky, a well known chess streamer. https://www.youtube.com/watch?v=pndmSw4Wq6Q

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Tags: online-chess, bullet-chess, chess-videos
---