# Question
Title: How to calculate FIDE's Perfect Tournament Performance (PTP)?
**How to calculate FIDE's PTP?**

The PTP is defined in https://handbook.fide.com/chapter/TieBreakRegulations042024 as:

> This is a whole number corresponding to the lowest rating that a participant should have for their expected score to be greater than or equal to their tournament score. For a zero score, this number is set 800 points The expected score is the sum of the scoring probabilities which are defined in the FIDE Rating Regulations by the conversion table of rating differences into scoring probabilities.
>
> Each rating difference is calculated by using the aforementioned lowest rating and **the rating of each opponent** faced by the participant during the tournament. The full rating scale is used in this conversion (i.e. no ±400 cut).

Since different ratings are discussed here, what is meant by *the rating of each opponent faced by the participant during the tournament*?

Is it:

1. the player's rating according to the actual FIDE Chess rating list,
2. or the Tournament Performance Rating as defined in chapter 10.2,
3. or recursively the Perfect Tournament Performance (PTP) rating itself?

# Answer
> 0 votes
"The rating of each opponent" has to be the opponent's rating according to the actual FIDE rating list.

"Performance rating" isn't mentioned in 10.3, so if they had meant the performance rating they would have said so.

They aren't going to make a recursive tiebreaker, especially with no hints on how to start calculating it (you can't calculate your tiebreaker until you calculate your opponents' tiebreaker, but since you're one of their opponents you can't calculate theirs until you calculate yours.) And again, they would have said PTP if they had meant that.

As support for "they would have said so", take a look at the wording in 10.4 and 10.5, where they do say so:

> 10.4 Average \[Tournament\] Performance Rating of Opponents (APRO)
> The average of the performances (TPR) of the opponents played over the board

> 10.5 Average Perfect \[Tournament\] Performance of Opponents (APPO)
> The average of the perfect performances (PTP) of the opponents played over the board, rounded to the nearest whole number (0.5 rounded up).

Compare that to 10.1, which also uses "rating" but clearly isn't using TPR or PTP because they aren't even defined yet:

> 10.1 Average Rating of Opponents (ARO)
> The average of the ratings of the opponents played over the board, rounded to the nearest whole number (0.5 rounded up).

So: "rating" is just the FIDE rating.

---
Tags: fide, rating
---


# Question
Title: What sites have different ratings for different time controls for Chess960?
Both lichess and chess.com and have ratings for live chess960, but this is regardless of time control. Please recommend a site that has separate ratings for different time controls for chess960.

There are always multiple accounts (I actually messaged both lichess and chess.com and then they approved me) or actually playing only rapid on one site and then only blitz on another, but come on.

# Answer
Chess.com will actually now give separate ratings for bullet/blitz/rapid for variants like 960. But you must go into the "4 player and variants" part of the site. If you play 960 on the regular part of the site (which it still lets you do) it just gives you one 960 rating as always.
> 1 votes

---
Tags: chess-variants, online-chess, chess960, recommendations
---


# Question
Title: Seeking a transcript of Hope vs. Fischer, 1972
On one of Bob Hope's television specials in 1972, Bobby Fischer appeared with him in a skit about himself (Fischer). The two also sat down at a board and sort-of played a game. (The moves were not all legal.) You can see the game on YouTube, but (at least I) can't see it well enough to know what the moves were. Can anyone tell what the moves were, or is there a record?

# Answer
Unfortunately I don't think this is possible. I think I can make out Fischer's first few moves (a rather reasonable e5, d5, Nf6, Bc5, O-O, Nc6) but it's much harder to make out what moves Hope is playing when he's not bound by logic nor the rules of chess. The blurriness and the illegal moves are bad enough, but they also change the position a few times when they cut to a different camera, meaning even when we get a better angle we can't even use the better view to determine what was played.

At 4:03 you can see Hope's king and queen in the correct position. When the camera cuts to Fischer, you can see the king and queen have spontaneously swapped places (which Fischer corrects two moves into the game.)

At 5:51 you can see clear down the 4th rank, so no pieces are there. But at 5:52-5:58 Hope clearly has a bishop on a4. At 5:59 he clearly does not, and there are other rather major changes to the position, despite neither player moving any pieces during that time.

So there were multiple takes (meaning there was no singular "game" shown in the first place) or portions were cut. Either way it is more or less impossible to fully recreate the game. I also highly doubt anyone saved a record of the game beyond the video itself. Any non-gag moves were likely not in the script.
> 4 votes

---
Tags: history, famous-games, fischer
---


title: "Every" move in long notation

text:
# Question
Title: "Every" move in long notation
A move here shall be defined as the FIDE super-long notation of a legal chess move: Sg1-f3, O-O, e5xd6 ep, Da8xg8+, Rd1-d6# and whatnot. I.e. starting square, ending square, capture sign, check sign, mate sign, ep (all if applies), castling. (Stalemate is usually not notated.) How many moves are possible? Danger, counting pitfalls: Bh1-a8 is never a check!

(I think this question might have been addressed in a problem chess journal already.)

# Answer
OK, let's break it down piece by piece, first calculating without check/checkmate and then with.

**Pawns**

Each pawn has 6 non-capturing non-promoting moves, and can promote to 4 different pieces. The rook pawns have, including en passant, 6 non-promotion captures and 4 promotion captures. The non-rook pawns have double the captures. This gives us 20 moves per rook pawn and 30 per non-rook pawn. There are 4 rook pawns and 12 non-rook pawns. 4 times 20 is 80, 12 times 30 is 360, added together is 440.

Every pawn move, including en passant and promotions, could be a check or checkmate. So triple that. 440 times 3 equals 1320 total pawn moves.

**Knights**

There are 16 squares a knight can move from which give it 8 places to go, 16 squares where it has 6 places to go, 20 squares where it has 4 places to go, 8 squares where it has 3 places to go, and 4 squares where it has 2 places to go. So that's 128 + 96 + 80 + 24 + 8 = 336.

There is no particular reason why a knight move couldn't be check or checkmate, and no particular reason why it couldn't be a capture, so multiply this by 6. 336 times 6 is 2016 total knight moves.

**Bishops**

From the center 4 squares, a bishop has 13 moves. From the 12 squares ringing the center, a bishop has 11 moves. From the 20 squares ringing *those* squares, a bishop has 9 moves, and from the 28 squares at the edge of the board, a bishop has 7 moves. So that's 52 + 132 + 180 + 196 = 560 bishop moves.

As warned in the question, some bishop moves cannot be check or checkmate. These would be the moves where the bishop cannot uncover another piece and does not control any new squares itself. Those moves turn out to be only the moves from one corner to another, of which there are 4. So, subtract those 4 before multiplying, 556 times 3 is 1668, add back those 4, and get 1672. Any of those could also be a capture, so 1672 times 2 = 3344 total bishop moves.

**Rooks**

Rooks are easy. Each rook has 14 moves from any spot on the board. 14 times 64 is 896.

Any of these moves could be a check or checkmate, and any of those could also be a capture, so 896 times 6 is 5376 total rook moves.

**Queens**

Queens can do any move the rook or bishop can do. 560 bishop moves plus 896 rook moves equals 1456.

Queens can give check on those corner to corner moves where the bishop can't, so all of these moves could be check or checkmate. And any of those moves could also be a capture. So we can simply multiply this by 6 and get 8736 total queen moves.

**Kings**

There are 36 squares where a king has 8 possible moves, 24 edge squares where it has 5 possible moves, and 4 corner squares where it has 3 possible moves. There are also 2 castling moves, which are classified as king moves. (I assume White castling and Black castling count as the same move since they use the same notation, even though the pieces move to different squares.) 288 + 120 + 12 + 2 = 422.

Kings can never give check directly; they can only give check if uncovering another piece - or by castling, where the rook can give check. The only way they can't uncover a piece is if they move from the corner (12 moves) or non-diagonally from an edge square to an edge or corner (48 moves). So subtract 60, 362 times 3 is 1086, add the 60 back, to get 1146. All of these except castling could also be captures. So there are 2286 total king moves.

**Sanity check**

Let's make sure these numbers make sense in relation to each other.

There are more queen moves than anything else, rook moves are second, bishops are third, kings are fourth, knights are fifth, and pawns are last, which makes intuitive sense.

**Total**

Now we can add it all up. 1320 + 2016 + 3344 + 5376 + 8736 + 2286 = **23,078** total moves.
> 2 votes

---
Tags: puzzles, mathematics, annotation
---


# Question
Title: "Daddy, why don't you take the e4 pawn?"
I play with my 8-year old daughter chess often and about half of our games start with these moves:

```
[FEN ""]
[StartFlipped "1"]
[StartPly "7"]

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7

```

Today after I (black) made the move Be7, my daughter asked me:

> Daddy, why don't you take the e4 pawn?

Well, I don't really know. I guess 5... Be7 the book move that I just play automatically. I know 5... b5 is also playable but far less common. I don't see top players take the e4 pawn often, except Magnus, who can play any opening, including the obviously dubious Bongcloud Attack.

But why not Knight takes e4 pawn?

My intuition is after 5... Nxe4, black has issues with the e-file and white can respond with 6. Re1. Then I realised that after 5... Nxe4, very few top players will continue with 6. Re1. The main move is actually 6. d4. (What's wrong with 6. Re1??)

So how do I answer her question:

**why don't you take the e4 pawn?**

# Answer
> 22 votes
# Open Ruy Lopez

**Nxe4** is indeed very legitimate - this is the Open Ruy Lopez and was very popular until the beginning of 20th century. There is nothing fundamentally wrong with it, it's just a bit overexplored. Lines are more tactical and sharper than in the closed (**Be7**) variation, so subsequently they are narrower, longer and thus easier to (over-)prepare.

A famous game in this variation is Smyslov vs Reshevsky, 1945, in which Smyslov didn't leave his preparation until at least 20th move. In comment Rkovach shared this anecdote about the particular subvariation in the game:

> Reshevsky sat for 45 minutes (!) on his 16th move. Shortly after receiving Smyslov's immediate reply, Reshevsky asked for time on Smyslov's clock - the response was "2 1/2 minutes" After several confirmations conviced him that it was indeed 2 1/2 minutes Al Horowitz came up, turned the score so he could read it and asked R "Sammy, have you kept up with the Russian journals? - Smyslov published 22 pages on this line and beats it in every variation" — Rkovach's comment

More recent example was played in this year Tata Steel: Firouzja vs Abdusattorov, 2024, with draw.

So in the end is a matter of taste and sporting concerns. If you are good at tactics and fine with fighting a long and forcing theoretical battle, **Nxe4** is perfect for you - just be aware that these long and forcing lines often fizzle out to quick draws and, that if you mess up, you will lose quickly. Otherwise go for **Be7**, but be prepared to deal with white having lasting pressure.

# 6. d4 or 6. Re1?

White side prefers to play **6. d4** to **6. Re1** due to **6. Re1 Nc5**. Position is similiar to Berlin variation, just a bit improved for black, since his knight is more active. Resulting positions are very drawish and tend to punish ambitious play for both sides. So if white is happy with quick draw he can go for **6. Re1**, but **6. d4** is way more promising.

# Popularity

As @IanBush commented the Open variation was played pretty much always - even today. However, since beginning of 20th century it was eclipsed first by popularity of closed variations and today by popularity of Berlin.

I made a quick plot based on Caissabase:

Where y-axes is % of all Ruys and open covers ECO codes **C80-C83** and closed ECO codes **C84-C99**.

# Answer
> 6 votes
> why don't you take the e4 pawn?

Taking the pawn is a valid move so far as I can tell. According to lichess's master database it scores about as well as Be7. But after White plays 6. d4, Black has the choice of giving the pawn back fairly quickly, or taking a second pawn with 6... exd4 and putting their e4 knight in some danger (White *will* play Re1 now that it directly pins the knight to the king, and Black must play carefully to avoid losing that knight.) It's certainly not just a free pawn if White knows what they are doing.

> (What's wrong with 6. Re1??)

According to WikiBooks:

> The natural 6. Re1 is in fact a very minor sideline; not only does it commit the rook to the e-file unnecessarily, but it allows Black's knight to retreat to c5, forcing the exchange of the a4-bishop. If Bxc6 dxc6, Black is then doing rather well compared to the Exchange Variation as the bishop has lost a tempo and the disappearance of the centre pawns favours Black's bishop pair.

---
Tags: opening, ruy-lopez, children
---


title: Sharp lines in the QGD, for black?

text:
# Question
Title: Sharp lines in the QGD, for black?
As a 1.e4 player who deeply enjoys sharp lines and studying/memorizing openings, I have always struggled with responding to 1.d4 since it leads to slow positional lines which usually have multiple correct answers/continuations. Over the years I have built up my repertoire and against the QG I usually play traditional main lines or Ragozin when permitted.

I want to change that. **What are some sharp variations in the QGD for black?** I am looking for the type of openings in which there exist multiple lines that involve many bad moves and few good moves.

I went over Lichess' opening explorer as I usually do and looked at the Baltic Defense (which I think seems to lead to boring drawn positions), Chigorin Defense (which seems to be equally unsharp as the main line), Austrian Defense (white has 5 playable choices by move 3 ... totally not sharp), etc. It seems that any reply to 1.d4 ... 2.c4... just leads to unsharp positions.

# Answer
> 3 votes
The thing is, that declining the gambit indeed leads to closed, more positional positions. I would recommend accepting the gambit and then playing e5 after e3 or e4. This is risky, but it does lead to more open and attacking positions.

# Answer
> 0 votes
There is a new course on the QGD, on chessable by IM Krishnater, it revolves around playing ragozin style positions uber dynamically, you might wanna check that out for an extremely dynamic approach. Otherwise, the modern QGD as has been used by kramnik, with Nbd7, h6 and c5, often accepting an IQP, is also viable and is seen in GM colovic's QGD LTR

---
Tags: opening, theory, queens-gambit-declined
---


title: Resources on the closed Italian

text:
# Question
Title: Resources on the closed Italian
What are some good books, courses, etc to learn the slow Italian with d3? I want to start playing the slow Italian with d3 as it keeps lots of pieces on the board and leads to rich middle games and am looking for resources to learn the opening

# Answer
# Book recommendations

On chess24 there was a very nice course by GM Ivan Šarić, however I don't know if it's still possible to get it today, due to Chess.com closing down chess24 on 31. 1. 2024.

I also liked Winning with the Slow (but Venomous!) Italian by Georgios Souleidis and Karsten Müller.

Let's focus first on the mainline with **c3** and **d3**.

# Move orders

When learning Italian I found it helpful to start with learning how to punish Black for wrong move order (why cannot he play **g6** at this or that point, how to deal with **f5**, ...) and then going for topical plans.

The hardest two move order issues for both players are timing of **O-O** and **h3**, **h6**. **h3** played too early can often be punished by **h6-g5** (if black didn't castle yet), while if not played it often allows **Ng4** shenaningans (targeting *f2*, which is weakened by **Rfe1**).

# Symmetry

Note that in most classical positions there is a lot of symmetry:

* Bishop on *c4* \- Bishop on *c5*
* Knight on *f3* \- Knight on *f6*
* Pawn on *e4* \- Pawn on *e5*

So plans are similiar for both sides. Concrete difference is that black has knight on *c6*, which is slightly misplaced, so he will have to reroute it, which gives white a small advantage in development. So Black main goal is to offset this development disadvantage and free his position with quick **d5**.

There are of course other plans for black (for example with **h6-g6-Bg7**), the main alternative being setup with **Be7**: **1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. d3 Be7**. Black will play for quick **d5**, often gambiting this pawn. Play is similiar to Marshall in Ruy Lopez.

# Topical plans for White

## Kingside attack

The most classical approach to quiet Italian for White and very effective even today, especially when combined with other plans. White is going to reroute his queenside knight to kingside (via **Nbd2-Nf1-Ng3** or **-Ne3**), so his knights will target very nice **f5** and **h4** squares.

Rook lift is also very common: **Rfe1-Re3-Rg3** or **-Rh3** and queen is also quick to join the fray.

## Central break

In quiet Italian you play **c3-d3** first, but you are still planning to go for **d4** later. When you push **d4** it often adds extra fuel to your kingside attack.

Before you go for central break you need to reinforce your *e4-pawn* with moves like **Bc4-Bb3-Bc2** and **Rfe1** (which often needs to be prepared with **h3**, due to weakening of *f2*, which Black can often punish with **Ng4**).

## Queenside expansion

This plan is more independent and more modern, but I think it's not strictly better or worse than upper two. You go for **a4-a5** or/and **b4-b5**. This has two pluses:

1. Far advanced queenside pawns will be advantage in many endgames;
2. If you get rid of your *c-pawn* (with **d4** pawn break), you have open *c-file*, targetting *c7*. Black cannot easily move his *c-pawn* if you have pawn on *b5*, so getting a rook on open *c-file* can be very efficient.

## Opening up f-file

This plan is more common for Black side, but it's sometimes also useful for White. You play **Be3**, hoping that black will play **Bxe3** (otherwise you have a choice between keeping the tension and exhancing bishops yourself). After **fxe3** your position has two benefits:

1. Open *f-file* is very useful for kingside attack;
2. Your central pawn mass (*e3,e4,d3*) is very mobile. Doubled pawns on *e-file* practically guarante you easy **d3-d4** push.

# Flexibility

I think the main benefit of Italian over other openings is that it's very flexible - there are a lot of sidelines and different move orders, so you can easily surpise your opponent, even if he prepared against you. For this to succeed though, you need to know some sidelines.

The one I like most is **1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. d3 Nf6 5. Nc3 d6 6. Bg5** with idea of **Nd5**. At some point you will have to play **Bxf6**, losing bishop pair, however you will get **d3-d4** push in exchange almost "for free". Positions can get a bit dry if black knows what he is doing though.

# Hidden complexity

These slower Italian lines may at first glance appear more quiet and easier to play than older **c3-d4** lines. However they aren't simple at all. Inaccuracies can often be punished only tactically and kingside attack is always lurking just under the surface (even if you don't actively play for it). They are sharper than they look and passive play by Black often leads to quick tactical wins for White.

What makes them truly complex though is subtle interaction between these main plans. You need to learn (and accurately evaluate) which plan is better in which position, which moves are good for multiple plans and which ones detriment particular plan (in favor of another). How to combine them, how to react appropriately to your opponent ideas?
> 1 votes

---
Tags: opening, books, recommendations, italian-game
---


title: Rossolimo attack resources

text:
# Question
Title: Rossolimo attack resources
I am in the middle of crafting my chess repertoire from scratch and have saved up quite a bit of money for the past 3 years and I want to buy resources that are most dynamic against a particular black response.

Against the Nc6 Sicilians I want to play the rossolimo and am looking for some resources that allow me to play this line dynamically.

# Answer
As you probably know, chessable contains an enormous amount of courses. To find the best fit to your need (here adding the Rossolimo to your repertoir) I would go as follows:

1. Go to chessable \> Tools \> Opening Explorer.
2. Insert your position of interest and hit "Search courses for Position":
3. A list of the available courses that include this position will appear:

In your case, make sure that it is a repertoir from White perspective. I would go for "Keep It Simple: 1. e4 - 2.0". Here is what the cover of the course says about the Sicilian:

> ♚ Take Black’s tactics out of the Sicilian. With the Rossolimo and Moscow variations with an early Bb5, you’ll disrupt Black’s usual tricks and set up a dominating center…or an endgame Black will hate you for
> 1 votes

---
Tags: 1.e4, repertoire
---


title: Trying to understand evaluation

text:
# Question
Title: Trying to understand evaluation
I'm looking at this position.

```
[Title "White to move: +10"]
[StartFlipped "0"]
[FEN "r3kb1r/2pnp1p1/p3Bn1p/8/Np1Pq3/4B3/PP21PPP/R2Q1RK w kq - 0 1"]

```

Material is even, and in my inexperience I don't see an immediate advantage as white. Meanwhile, Stockfish 16 (from chess.com, at a depth of 41) rates this position as +10. What am I missing? What's the clear advantage for white?

# Answer
> 2 votes
The clear advantage for white is development! Because of black not having a LSB and the placement of whites pieces, black cant trade off the E6 bishop after Qb3 protects the bishop.That bishop hems in the black kingside, effectively making black play down a rook and bishop (+8 materially speaking) and also note that black's king is in the centre of the board (worth a pawn at least,so +9 roughly speaking) and cant castle long as the queenside is busted so if white brings rooks to the C and E file black is completely paralysed. Although I am also surprised by the +10 eval, thought it would be closer to 8 ish

# Answer
> 2 votes
From a human perspective, this is what I see ...

* Black's king is very unsafe. White's is completely safe.
* The light squared weaknesses around black's king are devastating.
* White has the bishop pair in an open game and black has traded off their light squared bishop exacerbating the light square weaknesses caused by pushing both the f-pawn and the h-pawn.
* Black is down a rook for the nonce and his bishop is not helping much.
* The semi-open c-file is white's
* White has the initiative
* Good moves for white are very easy to find. Black is fighting to survive.
* White's plan is simple. Qb3, Rfe1, Rac1, d5, etc.

For me, engine evaluations are becoming less and less useful (see cool comment by @emdio below, however). I often get positions where SF 16 is evaluating the position +5 or +6 and I can't tell why. I feel bad saying that, but it is what it is. The engine is so strong, that it knows with almost certainty that it will win this position. For players at the master or club level, it's pretty clear white is better and should win. I would have said +4/5 if you showed me this position. If you put this position in the hands of any GM, they would win as white 999/1000 times.

Here is SF's scoring of each piece courtesy of @emdio

As you can see, the engine places massive value on the bishop on e6. It rates it slightly more valuable than the black queen!

---
Tags: evaluation
---


# Question
Title: What's the maximum number of pieces attacking a single square?
I'm thinking about developing an optimized chess database file format. I can record a single move in 12 bits: two squares, each one with two coordinates, where each one is a number from 1 to 8.

Algebraic notation only shows the destination square for a move and the piece's type (either blank for pawn or a letter for one of the five non-pawns), which is also 12 bits; but when two pieces of the same type can move to the same square, they're disambiguated by which file the piece was on before, which is another 8 options or 3 bits. (Castling could be encoded as a king move of two squares' distance, rather than being a special case like SAN does it.)

My idea was to encode the move with just the destination square, and when there's ambiguity, select which one of the pieces it can be by enumerating them in some standard order then indicating which one it is with some index.

How big should the space for this index be? What's the largest number of squares on which there can be pieces that all attack a particular square, and what's an example of such a position (so I can use it for testing)?

# Answer
Assuming you mean pieces of just one color, 15 can be attacking one square:

```
[fen "B3R3/7Q/3N1N2/2N3N1/3Kn3/2NP1PN1/3N1N2/4R3 w - - 0 1"]

```

The wrong-colored bishop is the only one that can't participate.
> 3 votes

---
Tags: computer-chess, database, attack
---


# Question
Title: What is the fastest possible stalemate by castling?
It is known what the fastest stalemate is. But what but is the fastest possible stalemate in which castling must be the last move?

**33 plies** is my best result so far.

```
[FEN ""]

1. e4 h5 2. Qxh5 d6 3. Qxh8 Bh3 4. Qxg7 Bxg2 5. Qxg8 Bxf1 6. Qxf7+ Kd7 7. Qxf8 Kc6 8. Qxd8 e5 9. Qxd6+ Kb5 10. Qxc7 Bd3 11. Qxb8 Bxc2 12. Qxa8 Bd1 13. Qxa7 Kc4 14. Qxb7 Kd3 15. Nf3 Kc2 16. Qb3+ Kxc1 17. O-O

```

Castling for a pin isn’t the only possible motivation though. Here is **another 33 plies** sequence that shows motivation in protecting pieces and guarding squares.

```
[FEN ""]

1. f4 e5 2. fxe5 d6 3. exd6 Qg5 4. dxc7 Ke7 5. cxb8=Q Qxg2 6. Qxc8 Qxh2 7. Qxa8 Qxg1 8. Qxa7 g5 9. Qxb7+ Ke6 10. Qxf7+ Ke5 11. Qxf8 Qh2 12. Qxg8 Qh5 13. Qxh8+ Kf4 14. Qxh7 Kg4 15. Bg2 Kg3 16. Qxh5 g4 17. O-O

```

# Answer
> 4 votes
I’ve found a way to reduce the count down to **31 plies.**

```
[FEN ""]

1. f4 e5 2. fxe5 d6 3. exd6 Qg5 dxc7 Qxg2 5. cxb8=Q Qxh2 Qxa7 Qxg1 7. Qxa8 Qg2 8. Bxg2 g5 9. Qxb7 g4 10. Qxc8+ Ke7 11. Qxf8+ Ke6 12. Qxf7+ Ke5 13. Qxg8 Kf4 14. Qxh8 h5 15. Qxh5 Kg3 16. O-O

```

White has only two non-capturing moves, the first pawn move and casting. Black uses up all of their moves without rest. Therefore, I think that 31 plies may be optimal unless a pawn capture can be shaved off.

# Answer
> 2 votes
27 piles

```
[FEN ""]

1. c4 a5 2. h4 h5 3. Qa4 Ra6 4. Qxa5 Rah6 5. Qxc7 f6 6. Qxd7+ Kf7 7. Qxb7 Qd3 8. Qxb8 Qh7 9. Qxc8 Kg6 10. g3 Kf7 11. Bg2 Kg6 12. Nh3 Kf7 13. Qe6+ Kg6 14. O-O 1/2-1/2

```

---
Tags: problems, castling, stalemate, records
---


title: Most delaying moves before checkmate

text:
# Question
Title: Most delaying moves before checkmate
Consider a position where if was player A's turn, they could make a series of moves ("the mating sequence") with forced mate.

However, it is player B's turn, and they can make a series of "delaying moves", which A needs to respond to. (Probably they are spite checks, but perhaps not necessarily). If A could proceed with the forced mate, it doesn't count as a delaying move.

At the end of the sequence of the delaying moves, A can play the exact same mating sequence to win. (The mating sequence doesn't need to be one fixed sequence of moves played regardless of B's moves, as long as the tree of moves is unaffected by the delaying moves.)

Puzzle/Question: What is the longest (finite) sequence of delaying moves?

# Answer
If we rewind this problem back by a move, we have a delay of **100 moves.**

```
[Title "Frederik Willem Nanning, Tijdschrift van den Koninklijken Nederlandschen Schaakbond 1935, Mate in 100"]
[FEN "8/p1p1p3/2p3p1/6Pb/p3P1kr/P1p1PNn1/2P1PKRp/7B b - - 0 1"]
[startflipped ""]

1... Rh3 2. Ke1 Rh4 3. Kd1 Rh3 4. Kc1 Rh4 5. Kb1 Rh3 6. Ka2 Rh4 7. Ka1 Rh3 8. Kb1 Rh4 9. Kc1 Rh3 10. Kd1 Rh4 11. Ke1 Rh3 12. Kf2 a6 13. Ke1 Rh4 14. Kd1 Rh3 15. Kc1 Rh4 16. Kb1 Rh3 17. Ka2 Rh4 18. Ka1 Rh3 19. Kb1 Rh4 20. Kc1 Rh3 21. Kd1 Rh4 22. Ke1 Rh3 23. Kf2 a5 24. Ke1 Rh4 25. Kd1 Rh3 26. Kc1 Rh4 27. Kb1 Rh3 28. Ka2 Rh4 29. Ka1 Rh3 30. Kb1 Rh4 31. Kc1 Rh3 32. Kd1 Rh4 33. Ke1 Rh3 34. Kf2 c5 35. Ke1 Rh4 36. Kd1 Rh3 37. Kc1 Rh4 38. Kb1 Rh3 39. Ka2 Rh4 40. Ka1 Rh3 41. Kb1 Rh4 42. Kc1 Rh3 43. Kd1 Rh4 44. Ke1 Rh3 45. Kf2 c4 46. Ke1 Rh4 47. Kd1 Rh3 48. Kc1 Rh4 49. Kb1 Rh3 50. Ka2 Rh4 51. Ka1 Rh3 52. Kb1 Rh4 53. Kc1 Rh3 54. Kd1 Rh4 55. Ke1 Rh3 56. Kf2 c6 57. Ke1 Rh4 58. Kd1 Rh3 59. Kc1 Rh4 60. Kb1 Rh3 61. Ka2 Rh4 62. Ka1 Rh3 63. Kb1 Rh4 64. Kc1 Rh3 65. Kd1 Rh4 66. Ke1 Rh3 67. Kf2 c5 68. Ke1 Rh4 69. Kd1 Rh3 70. Kc1 Rh4 71. Kb1 Rh3 72. Ka2 Rh4 73. Ka1 Rh3 74. Kb1 Rh4 75. Kc1 Rh3 76. Kd1 Rh4 77. Ke1 Rh3 78. Kf2 e6 79. Ke1 Rh4 80. Kd1 Rh3 81. Kc1 Rh4 82. Kb1 Rh3 83. Ka2 Rh4 84. Ka1 Rh3 85. Kb1 Rh4 86. Kc1 Rh3 87. Kd1 Rh4 88. Ke1 Rh3 89. Kf2 e5 90. Ke1 Rh4 91. Kd1 Rh3 92. Kc1 Rh4 93. Kb1 Rh3 94. Ka2 Rh4 95. Ka1 Rh3 96. Kb1 Rh4 97. Kc1 Rh3 98. Kd1 Rh4 99. Ke1 Rh3 100. Kf2 Rh4 101. Rxg3#

```
> 2 votes

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


# Question
Title: More accurate estimate of chess games possible
I have heard of Shannon's number (10^120) which is the supposed number of possible chess games computed in the 1950s. But Shannon's estimate is criticised for including illegal moves. What is a truer estimate under the given parameter

1. no illegal positions
2. FIDE rules of 3 fold rep and 50 moves are in force
3. we start from the regular starting position

# Answer
> 3 votes
Peruse this link. Also see link for possible duplicate.

Sum-up of first link:

* Longest game under FIDE rules: 8848.5 (Fabel)
* Maximum mobility number: 218 moves
* Shannon's number, assuming 40 (full) moves, 30 moves per ply, ignoring FIDE rules and duplicates: 10^120
* Upper bound: 10^34082
* Realistic lower bound (Monte Carlo): 10^29241

---
Tags: computer-chess, mathematics, game-complexity
---


# Question
Title: I downloaded stockfish 15 ,the POPCNT version. It downloaded, but I don't know how to open it to play chess. Can you help me?
I downloaded stockfish 15 ,the POPCNT version. It downloaded, but I don't know how to open it to play chess. Can you help me?

# Answer
> 8 votes
Stockfish is not a chess *program*. It is a chess *engine*. It works together with a chess GUI, some of which cost money, like Fritz or Shredder, some of which are free, like Scid vs PC or Arena.

# Answer
> 6 votes
It's much easier to play Stockfish with the use of a GUI, but it's possible to manually use the stockfish executable via the command line if you want.

1. Go to the folder where you've installed stockfish.
2. Open a terminal (e.g., on windows it could be powershell), and run stockfish with "./" followed by the name of the stockfish executable (no spaces). E.g., "./stockfish", if you had renamed your executable to "stockfish".

There are now a number of commands you can use. For a list of them and some explanations, go to https://github.com/official-stockfish/Stockfish, and then go to the section called "The UCI protocol and available options". There you'll be able to download the UCI protocol text file.

The main commands you'll probably want are the ones starting with "go depth ...", "position ...", and "d". The "go depth ..." gets Stockfish to go to a certain depth and return what it believes to be the best move. The "position ..." commands let you set a new position, which you can do when getting what Stockfish wants to move, or what you want to move. Finally, "d" displays a visual of the position to you.

# Answer
> -1 votes
I installed en-croissant and add it as a engine. https://encroissant.org/ https://github.com/franciscoBSalgueiro/en-croissant And add a big free database.

---
Tags: stockfish
---


# Question
Title: Why was 20.Qe3 so good in Botvinnik-Sorokin?
Why was 20.Qe3 so good in Botvinnik-Sorokin?

It doubles the pawns, and doesn’t do much else.

# Answer
First of all, it was played by Botvinnik, a strong World Champion, and one of the most logical players ever, so it clearly has to do more than just let black ruin the white pawns.

It does many things:

1. It trades off black’s best piece, the active Qc5, and it cannot be avoided with Qc7? Nxe5!. Trading your opponent's active pieces is very desirable, and I suspect this was the primary motivation for Botvinnik even looking at Qe3.
2. Despite the fact that those pawns have been weakened, they control many critical squares. They are also very hard to get at, so although they may matter in the endgame, black cannot attack them anytime soon, and other factors will be much more important.
3. This is a principle that is not seen often, and often missed by weaker players, but sometimes when you trade down material when attacking, particularly, trading off a good defender, it allows the remaining pieces to strengthen, and they become unopposed. In this case, the doubled rooks are now monsters, and white’s significant lead in development is going to show even more.
4. How does black develop the Bc8? In the game, he chose g4 but soon actually had to strengthen white’s pawns after all.
5. Lastly, black is going to have a hard time defending e5, and it is attacked immediately.

The minor weakness, that black can't even get near, was nothing compared to the weaknesses that were exposed when the black queen was no longer on the board to defend them. In short, the Qc5 was the glue that held the black position together, and without it, there was no defense.

```
 [FEN ""]
 [Event "URS-ch07 Final"]
 [Site "Moscow"]
 [Date "1931.10.25"]
 [Round "2"]
 [White "Botvinnik, Mikhail Moisevich"]
 [Black "Sorokin, Nikolay Tikhovich"]
 [Result "1-0"]
 [ECO "D60"]

 1. d4 d5 2. Nf3 Nf6 3. c4 e6 4. Nc3 Nbd7 5. Bg5 Be7 6. e3 O-O 7. Bd3 c6 8. O-O a6 9. a4 dxc4 10. Bxc4 c5 11. dxc5 Bxc5 12. Qe2 h6 13. Bh4 Be7 14. Rfd1 Nh5 15. Bxe7 Qxe7 16. Rd2 Nb6 17. Rad1 Qc5 18. Ba2 Nf6 19. e4 e5 20. Qe3 Qxe3 (20...Qc7? 21. Nxe5!) 21. fxe3 Bg4 22. a5 Nc8 23. Rc1 Bxf3 24. gxf3 Ne7 25. Nd5 Nc6 26. Nxf6+ gxf6 27. Rd7 Rab8 28. Kf2 Nxa5 29. Rcc7 Rbc8 30. Rxf7 Rxc7 31. Rxc7+ Kh8 32. Bd5 b5 33. b3 Rd8 34. Kg3 f5 35. Kh4 fxe4 36. fxe4 Rd6 37. Kh5 Rf6 38. h3 Rd6 39. h4 Rb6 40. Kg4 Rf6 41. Ra7 Rb6 42. Re7 Rd6 43. Rc7 Rf6 44. Ra7 Rb6 45. Rc7 Rf6 46. Kh5 Rd6 47. Bf7 Rf6 48. Bg6 Nxb3 49. Kxh6 Rf8 50. Rh7+ Kg8 51. Rg7+ Kh8 52. Bf7 Rxf7 53. Rxf7 Kg8 54. Kg6 Nd2 55. Rd7 1-0

```
> 3 votes

# Answer
Move 20.Qe3? is actually very weak and misses the win. The winning move was 20.Rd6! This was all known more than 10 years ago - https://chesspro.ru/card\_index/smoktiy_
> 0 votes

---
Tags: strategy, botvinnik
---


# Question
Title: How can I register to FIDE being in a different country where I don't have citizenship or residency?
I come from Bangladesh and I am doing my bachelor's degree in Australia as an international student. Unfortunately, I didn't register with FIDE under the Bangladesh Chess Federation when I was in my country and I am not able to go back to my country within the next few years. However, I really want to start playing rated tournaments. How can I now register so that I can play FIDE rated tournaments?

I have been thinking of these two possibilities:

1. Register under FIDE flag if possible?
2. Register for a FIDE rated tournament in Bangladesh. Since I won't be showing up in the tournament, is it going to impact my registration?

# Answer
> 1 votes
If you play your first FIDE open tournament and obtain a FIDE rating, it is highly likely that you will be registered with the federation that organized that tournament. Later, if you wish, you can switch to another federation (It is not a difficult process). In general, being part of a national chess federation does not require citizenship of that country.

However, I advise you to focus on your academic duties. If you want to play FIDE chess tournaments while in college, you need to plan carefully. Otherwise, you can be in trouble. It is difficult to succeed on both fields. For example, you can play during the summer. Online chess is more flexible. Good luck!

---
Tags: fide, tournament
---


title: How play this rook end game

text:
# Question
Title: How play this rook end game
In the video Can 3 Women Beat A Grandmaster?

https://youtu.be/umCJkXuow9I?si=a-aHT-SrbNdcgJU\_&t=1071

* White: Dina Belenkaya
* Black: Danya Naroditsky

Engine show white are winning, but the thing was Dina didn't know how to play it and Danya on the other hand did know.

I can see black was countering every white move, so I guess there is a sequence of move for white to allow gain a tempo and allow them to move the points.

White just move the rook. So curious what those move sequence will be.

# Answer
White's best moves depend on what moves Black plays, of course, but it could go something like this:

```
[FEN "8/3R1K1k/2r4P/6P1/8/8/8/8 b - - 0 1"]

1... Rg6 2. Rd5 Ra6 3. Rd1 Ra7+ 4. Kf6 {The only winning move here!} (4. Ke6?? Kg6 {This is drawn.}) Ra6+ 5. Ke5 (5... Kg6 6. Rd6+) Ra5+ 6. Rd5 Ra6 7. Rd6 Ra5+ 8. Kf6 Ra7 9. Re6 Ra1 (9... Rb7 10. Re7+)  (9... Ra8 10. Re7+ Kh8 11. g6 {White is now threatening mate if Black's rook leaves the bank rank without check.} Rf8+ 12. Kg5 Ra8 13. Re5 Rg8 14. Rd5 Rb8 15. h7 Kg7 16. Rd7+ Kh8 17. Kh6 {Threatens g7#} Rg8 18. hxg8=Q+ Kxg8 19. Rd8#) 10. Re7+ Kg8 11. Re8+ Kh7 12. g6+ Kxh6 13. Rh8#

```
> 3 votes

---
Tags: rook-endgame
---


# Question
Title: Longest checkmates with the biggest material disadvantages in "open" positions?
We can ask a question:

* What are the longest checkmates with the biggest material disadvantages? What, approximately, is the function between length of the checkmate and possible size of the material disadvantage? (I.e. what is the biggest possible disadvantage for a 10 move checkmate? 20 moves? 30? 40?)

If we ask that question, we'll mostly get answers where one side's extra material is hopelessly isolated. See "context examples".

So, the question I actually want to ask is more specific:

* What are the longest checkmates with the biggest material disadvantages and positions which are as "open" as possible? (I.e. positions where one side's extra pieces aren't hopelessly isolated and aren't completely useless. See "example answers".) What, approximately, is the function between length of the checkmate and possible size of the material disadvantage?

**Caveat 1:** what matters is not only material disadvantage in the initial position, but the disadvantage throughout the checkmating variation. We're looking at material disadvantage at each move or even each half-move. We're asking *"how long is the checkmating side down material?"* and *"how long is the checkmating side down at least N points of material?"*. If we have a position with checkmate in 100 moves, but the winning side is down material only the first 50 moves, then only the first 50 moves matter (or even less, if we're looking for specific N and the winning side is N points of material down less than 50 moves). Those rules are not set in stone, though. The main point is just that we care how material balance evolves throughout the variation. Material is counted with the standard value of pieces (Queen = 9, Rook = 5, Bishop or Knight = 3, Pawn = 1).

**Caveat 2:** illegal positions are allowed.

All positions below are created by me except where stated otherwise.

# Context examples

```
[White ""]
[Black ""]
[FEN "brbqqqqq/rbrqqqqq/brbrqqqq/rbKbqqqq/brbrqqqq/rbrbqqqq/bPbrqqqq/kbrqqqqq w - - 0 1"]

1. bxc3 Kb2 2. cxb4 Kc3 3. bxa5 Kb2 4. axb6 Ka1 5. bxa7 Kb2 6. axb8=B Kc3 7. Ba7 Kb2 8. Bb6 Kc3 9. Ba5+ Kb2 10. Bb4 Ka1 11. Bc3#

```

In this position, White gives checkmate in 11 moves while never being less than **384** points of material down. Which means that at each move (even each half-move) of the variation White is down at least **384** points. But in the initial position White is down **416** points.

All credit goes to MonkeyBusiness and Cleveland. I've only insignificantly modified the position.

```
[White ""]
[Black ""]
[FEN "nRB4b/K1k5/pppppppn/qqqqqqrb/qqqqqqqq/qqqqqqqq/qqqqqqqq/qqqqqqqq w - - 0 1"]

1. Rb7+ Kd8 2. Rh7 Bg7 3. Rxg7 Ke8 4. Rb7 Nf7 5. Kxa8 Nd8 6. Ra7 Nf7 7. Kb8 Nh6 8. Kc7 Kf7 9. Bd7 Kf8 10. Ra8+ Ke7 11. Rc8 Kf7 12. Kd8 Kf8 13. Be8 Kg7 14. Rc7+ Kf8 15. Rb7 Kg8 16. Ke7 Kg7 17. Bf7 Nxf7 (17... Kh7 18. Kf8 Kh8 19. Bg8 Nxg8 20. Ra7 Nh6 21. Rg7 Nf7 22. Rg8+ Kh7 23. Kxf7 Kh6 24. Rh8#) 18. Ke8 Kg8 19. Rxf7 Kh8 20. Rf8+ Kg7 21. Ke7 Kh6 22. Kf7 Kh7 23. Rc8 Kh6 24. Rh8#

```

In this position, White gives checkmate in 20+ moves while never being less than **352** points down. And White starts **358** points down.

We could also build upon the ideas of Boris Sidorov (1983, #22, 22 moves) and Otto Blathy (1922, win, 14 moves).

However, you can notice that in those positions extra material is completely isolated. In the last two examples the isolation is not absolute, but most of the extra pieces are completely useless (e.g. they can only be sacrificed in exactly the same way). What could we achieve in much more "open" positions where a bigger portion of the extra pieces are useful?

# Example answers

```
[White ""]
[Black ""]
[FEN "qrqqqqqq/qqqqqBqN/qrrPnpqq/Nnr1nppr/qrBNPq1b/rP1B1p1k/pPQPQQRP/nNBNKR1b w - - 1 1"]

```

(I haven't included the solution in the diagram because you may want to experience it blind: https://lichess.org/study/hBcBtt33. If you want to reveal the next move - click "reveal the solution", it doesn't reveal the whole thing.)

This is a candidate position for a checkmate in 30+ moves while always being at least **126** points down throughout the entire variation. I verified the position in different ways (with Stockfish), but maybe there's still some super obscure line which computer missed.

Here's the link to immediately access the full solution and positions for verification and extention: https://lichess.org/study/v0lPLC2T.

```
[White ""]
[Black ""]
[FEN "b2b1Rqb/Nnp2brR/1pN1N1Pq/n2K4/pP6/2k1Pp1n/Rpp3br/rbBbrrqq w - - 0 1"]

1. Nb5+ Kd3 2. Ne5+ Ke2 3. Nc3+ Kf2 4. Nd3+ Kg3 5. Ne4+ Kg4 (5... Kh4?? 6. Rxh6+ Kg4 7. Ne5+ Kf5 8. Ng3+ Kf6 9. gxf7+ Rg6) 6. Ne5+ Kf5 (6... Kh5?? 7. Ng3+ Kh4 8. Nf5+ Kh5 9. Rxh6#) 7. Ng3+ Kf6 8. Ng4+ Ke7 9. Nf5+ Kd7 10. Ne5+ Kc8 11. Ne7+ Kb8 12. Nd7+ Ka7 13. Nc8+ Ka6 14. Nb8+ Kb5 15. Na7+ Kxb4 16. Na6+ Kc3 17. Nb5+ Kd3 18. Nb4+ Ke2 19. Nc3+ Kf2 20. Nd3+ Kg3 21. Ne4+ Kg4 22. Ne5+ Kf5 23. Ng3+ Kf6 24. Ng4+ Ke7 25. Nf5+ Kd7 26. Ne5+ Kc8 27. Ne7+ Kb8 28. Nd7+ Ka7 29. Nc8+ Ka6 30. Nb8+ Kb5 31. Rxb2+ Nb3 32. Na7+ Kb4 (32... Ka5?? 33. Bd2+ Nxd2 34. Rb5#) 33. Nbc6+ Kc3 34. Nb5+ Kd3 35. Nb4+ Ke2 36. Nc3+ Kf2 37. Nd3+ Kg3 38. Ne4+ Kg4 39. Ne5+ Kf5 40. Ng3+ Kf6 41. Ng4+ Ke7 42. Nf5+ Kd7 43. Ne5+ Kc8 44. Ne7+ Kb8 45. N5c6#

```

In this position, White gives checkmate in 45 moves while never being less than **67** points down. The position is a bastardized version of a composition by Otto Blathy and Heinrich Meyer. There White is only **17** points down.

It's potentially bad that all White's moves are checks though (most of Black's pieces are effectively frozen in place). So, here's another position:

```
[White ""]
[Black ""]
[FEN "rn2Qqrb/qq1nRb2/Nqp1nqkp/1q2PppR/RprpnQRp/brpPQrR1/qPPN2P1/rbBRK2R w - - 6 1"]

1. Rgxg5+ N4xg5 2. Qxg5+ Nxg5 3. Qxg5+ Qxg5 4. Rgxg5+ hxg5 5. Rxg5+ Kxg5 6. Nxf3+ Kh5 (6... Kg6?? 7. Nxh4+ Kh5 8. g4+ fxg4 9. Nf5+ Kg6 10. Rh6+ Kxf5 11. Rxf7+ Qxf7 12. Qxf7+ Nf6 13. Rxf6+ Kxe5 14. Bf4#) 7. Rxh4+ Kg6 8. Rh6+ Kg7 9. Rxf7+ Qxf7 10. Rh7+ Kxh7 11. Qxf7+ Rg7 12. Ng5+ Kh6 13. Ne4+ Kh7 (13... f4?? 14. Bxf4+ Kh7 15. Ng5+ Kh6 16. Qe6+ Nf6 17. Qxf6+ Kh5 18. Kf2!! Bxc2 19. Qf5!! Qxe5 20. g4+ Kh4 21. Nf3+ Kh3 22. Bxe5 Qf7 23. Ng1+ Kh4 24. Bg3#) 14. Qh5+ Kg8 15. Qe8+ Kh7 16. Kf2!! Rxg2+ 17. Kxg2 Nf8 18. Rh1+ Kg8 19. Rxh8+ Kxh8 20. Qxf8+ Kh7 21. Ng5+ Kg6 22. Qf6+ Kh5 23. Ne6!! Qg7+ 24. Nxg7+ Qxg7+ 25. Qxg7 Qd5+ (25... f4?? 26. Qf7+ Kg5 27. Qxf4+ Kg6 28. Qh6+ Kf7 29. Qh7+ Ke8 30. Qh5+ Kd8 31. Qh8+ Kd7 32. Qh3+ Ke7 33. Bg5+ Kf7 34. Qf5+ Kg7 35. Qf6+ Kg8 36. Qg6+ Kf8 37. Bh6+ Ke7 38. Qd6+ Kf7 39. Qf6+ Ke8 40. Qe6+ Kd8 41. Bg5#) 26. Kg3!! Qxe5+ 27. Qxe5 Kg6 28. Qe6+ Kg7 29. Qh6+ Kg8 (29... Kf7? 30. Qh7+ Ke6 31. Qg6+ Kd7 32. Qxf5+ Ke7 33. Bg5+ Kd6 34. Qf7!! c5 35. Bf4+ Kc6 36. Nc7!! Qa5 37. Qd5+ Kb6 38. Nxa8+ Kb5 39. Rxa5+ Kxa5 40. Qe6!? Bxb2 41. Qb6+ Ka4 42. Bxb8 Bxc2 43. Qa6#) 30. Qg6+ Kh8 (30... Kf8? 31. Bh6+ Ke7 32. Bg5+) 31. Bf4!! Qb5 32. Nc7!! Na6 (32... Rxa4?? 33. Qf6+ Kh7 34. Qe7+ Kg8 35. Bh6 Qe5+ 36. Qxe5 f4+ 37. Kxf4 Kf7 38. Qg7#) 33. Qh6+!? Kg8 34. Ne6!! Ra7 35. Qf8+ Kh7 36. Ng5+ Kg6 37. Rxa6 Bxb2 38. Qg8+ Kf6 39. Nh7+ Ke7 40. Bg5+ Kd6 41. Qd8+ Rd7 42. Be7+ Ke6 43. Ng5+ Ke5 44. Qh8+ Kd5 45. Qg8+ Ke5 46. Nf3#

```

In this position, White gives checkmate in 46 moves while never being less than **26** points down. Unlike in the previous example, here there's plenty of non-check moves.

It stands to reason that with 40+ checkmates we're approaching the absolute ceiling for large disadvantages in "open" positions.

# Answer
Stealing from myself, and presuming I fine tuned it correctly, here is a difference of 309-37=**272 points**.

```
[Title "me, chess.stackexchange.com 3/2/2024, Mate In 65"]
[FEN "qqqqqB1k/1qqqqB2/q1qqqp2/qq1qqNR1/qqq1qBnN/qqqr1RPR/qqqqqqPK/qRqRqR1b w - - 0 1"]

1. Rxg4 Qxg1+ 2. Rxg1 Qxg1+ 3. Rxg1 Qxg1+ 4. Rxg1 Qxg1+ 5. Kxg1 Qee1+ 6. Kh2 Qg1+ 7. Kxg1 Qdd1+ 8. Kh2 Qg1+ 9. Kxg1 Qcc1+ 10. Kh2 Qg1+ 11. Kxg1 Qbb1+ 12. Kh2 Qg1+ 13. Kxg1 Qaa1+ 14. Kh2 Qg1+ 15. Kxg1 Qaa1+ 16. Kh2 Qg1+ 17. Kxg1 Qaa1+ 18. Kh2 Qg1+ 19. Kxg1 Qaa1+ 20. Kh2 Qg1+ 21. Kxg1 Qaa1+ 22. Kh2 Qg1+ 23. Kxg1 Qaa1+ 24. Kh2 Qg1+ 25. Kxg1 Qb1+ 26. Kh2 Qg1+ 27. Kxg1 Qb1+ 28. Kh2 Qg1+ 29. Kxg1 Qb1+ 30. Kh2 Qg1+ 31. Kxg1 Qb1+ 32. Kh2 Qg1+ 33. Kxg1 Qb1+ 34. Kh2 Qg1+ 35. Kxg1 Qc1+ 36. Kh2 Qg1+ 37. Kxg1 Qc1+ 38. Kh2 Qg1+ 39. Kxg1 Qc1+ 40. Kh2 Qg1+ 41. Kxg1 Qc1+ 42. Kh2 Qg1+ 43. Kxg1 Qcc5+ 44. Kh2 Qg1+ 45. Kxg1 Qdd4+ 46. Kh2 Qg1+ 47. Kxg1 Qdd4+ 48. Kh2 Qg1+ 49. Kxg1 Qdd4+ 50. Kh2 Qg1+ 51. Kxg1 Qdd4+ 52. Kh2 Qg1+ 53. Kxg1 Qe1+ 54. Kh2 Qg1+ 55. Kxg1 Qe1+ 56. Kh2 Qg1+ 57. Kxg1 Qe1+ 58. Kh2 Qg1+ 59. Kxg1 Qe1+ 60. Kh2 Qg1+ 61. Kxg1 Qe1+ 62. Kh2 Qg1+ 63. Kxg1 Rd1+ 64. Kh2 Bxg2 65. Ng6#

```
> 1 votes

---
Tags: problems, records, mathematics
---


# Question
Title: How to play as black in the exchange Caro-Kann?
I used to be a Caro-Kann player and had great results in it against all lines except the exchange variation. I had a horrible score there and I wish to remedy that.

What are some good middlegame plans for black in the exchange Caro-Kann?

I am aware of the Carlsbad structure (was an exchange Queen's Gambit Declined player,but there I always used the f3-e4 central pawn push as the gameplan) but it just seems like black's queenside play is too slow.

# Answer
There is one important difference between **Queen Gambit Exchange** and **Caro-Kann Exchange** \- while structure is same (with colours reversed), white has in QGE a few tempos more than black has in C-K. So kingside play for white in C-K is much more effective than it is for black in QGE.

So in C-K you have a choice between two approaches:

1. Classical lines beginning with **1. e4 c6 2. d4 d5 3. exd5 cxd5 4. Bd3 Nc6 5. c3 Nf6 6. Bf4 Bg4**;
2. More modern approaches, for example starting from **1. e4 c6 2. d4 d5 3. exd5 cxd5 4. Bd3 Nc6 5. c3 Qc7**.

# 1. Classical approach

There black is planning to eventually go for minority attack. However, white will get some serious initiative on the kingside, so black first has to survive. Rule of thumb is: **minority attack is serious option for black if two pairs of minor pieces were exchanged**. So be careful on the kingside (**Bxh7** sac is very common), exchange pieces and then start working on the queenside.

These lines are a bit stodgy, since white has long-term advantage due to having better light-squared bishop or bishop pair (if black decided to play **Bxf3**). However if you know them well they are reliably drawish.

I think best option for black in this complex is **1. e4 c6 2. d4 d5 3. exd5 cxd5 4. Bd3 Nc6 5. c3 Nf6 6. Bf4 Bg4 7. Qb3 Qd7 8. Nd2 e6 9. Ngf3 Bxf3 10. Nxf3 Bd6 11. Bxd6 Qxd6**, where white has only slight advantage due to good light-squared bishop. Note that white can try **Qxb7**, but black has very good compensation for the pawn.

# 2. Modern approach

There black is planning to go for **e5** break, hopping for good IQP positions. Sometimes he prepares it with **f6** first, but this is usually too slow and weakening. If white knows his stuff he may get quite an advantage. So playing **e5** straight away is better.

Another common option is to go for **g6** first and prepare **e5** later, or maybe go for **Bf5** with idea of opening up g-file for attack on the kingside.

The line I like facing the least with white pieces is **1. e4 c6 2. d4 d5 3. exd5 cxd5 4. Bd3 Nc6 5. c3 Qc7**. Black now prevented **Bf4**. Now best for white is to go for a tad disappointing **6. h3**, since if he decides to prepare **Bf4** he quickly lands in trouble, for example after very natural: **1. e4 c6 2. d4 d5 3. exd5 cxd5 4. Bd3 Nc6 5. c3 Qc7 6. Ne2?! Bg4 7. f3?! Bd7 8. Bf4 e5!**, where black is a bit better.

# Further reading

About these lines and development of theory in C-K there are two very good surveys on Perlen vom Bodensee's website:

1. How to tackle the Caro Kann Exchange: an urgent recommendation (Opening Survey)
2. Winning after 17 moves against Aronian: an expansion on our Caro Kann survey, forced by fabulous Fabi
> 4 votes

# Answer
As Black, you can either play for ...f6 and ...e5 in the exchange Caro-Kann, or you can play for a **minority attack** with the a- and b-pawns. You can check out *Chess structures: a grandmaster guide* by Mauricio Flores Rios. He has a chapter on this Carlsbad structure, albeit that he assumes White has to play for the f3 and e4 break or choose the minority attack.
> 0 votes

---
Tags: strategy, middlegame, caro-kann
---


# Question
Title: Any functional Stockfish online API in 2024? (preferably with WebSocket support)
I'm on the hunt for an online Stockfish API where I can send either a FEN/PGN position or a list of moves and get back some info like evaluations / variants / best moves.

I've been scouring StackExchange posts, but most of the services I've found seem to have gone AWOL. I stumbled upon the stockifish.online website, but it's a bit sluggish and doesn't offer much data.

Got any other leads?

# Answer
> 3 votes
I found https://chess-api.com/. Quite easy but has limited depth (18). Runs SF 16.1 NNUE.

Example POST request:

```
async function postChessApi(data = {}) {
    const response = await fetch("https://chess-api.com/v1", {
        method: "POST",
        headers: {
            "Content-Type": "application/json"
        },
        body: JSON.stringify(data),
    });
    return response.json();
}

```

```
postChessApi({ fen: "7Q/8/8/6k1/2K5/8/8/8 w - -", depth: 30, variants: 1 }).then((data) => {
    console.log(data);
});

```

Response:

```
{
    "text": "Move h8 → e5 (Qe5+): [100]. White is winning. Depth 18.",
    "captured": false,
    "promotion": false,
    "isCapture": false,
    "isPromotion": false,
    "isCastling": false,
    "fen": "7Q/8/8/6k1/2K5/8/8/8 w - - 0 1",
    "type": "bestmove",
    "depth": 18,
    "move": "h8e5",
    "eval": 100,
    "centipawns": 10000,
    "mate": "13",
    "continuationArr": [
        "g5g6",
        "e5e6",
        "g6g5",
        "c4d4",
        "g5f4",
        "e6f6",
        "f4g3",
        "f6f5",
        "g3g2",
        "d4d3",
        "g2g3",
        "d3e2",
        "g3h4",
        "e2e3",
        "h4g3",
        "f5g5",
        "g3h2"
    ],
    "debug": "info depth 18 seldepth 21 multipv 1 score mate 13 nodes 98918 nps 32972666 hashfull 15 tbhits 0 time 3 pv h8e5 g5g6 e5e6 g6g5 c4d4 g5f4 e6f6 f4g3 f6f5 g3g2 d4d3 g2g3 d3e2 g3h4 e2e3 h4g3 f5g5 g3h2",
    "winChance": 100,
    "taskId": "8w3cp3pf1",
    "turn": "w",
    "color": "w",
    "piece": "q",
    "from": "h8",
    "to": "e5",
    "san": "Qe5+",
    "flags": "n",
    "lan": "h8e5",
    "fromNumeric": "88",
    "toNumeric": "55",
    "continuation": [
        {
            "from": "g5",
            "to": "g6",
            "fromNumeric": "75",
            "toNumeric": "76"
        },
        {
            "from": "e5",
            "to": "e6",
            "fromNumeric": "55",
            "toNumeric": "56"
        }
    ]
}

```

# Answer
> 2 votes
I think it's unlikely that you will find publically accessible API like this, since engines aren't cheap to run on scale.

However you can get pretty close. First option is Lichess cloud evaluations database that exposes engine evaluations for 15 million positions via API. Data available is analysis depth, kilonodes and best variations.

If you are prepared to host engine yourself and just need to make it accessible via API it's possible with Lichess external engine API.

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


# Question
Title: Is there an online chess evaluation engine with a REST API?
Is there an online chess evaluation engine with a REST API? I'd like to be able to send a game or position (with castling ability presumably) to a simple REST API and get back the positional evaluation from a reasonably strong engine.

# Answer
> 4 votes
The project https://github.com/noobpwnftw/chessdb provides an API for getting engine evaluations including also the PV, with the FEN of a position as input.

E.g., try an example from the readme:

https://www.chessdb.cn/cdb.php?action=querypv&board=rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR%20w%20KQkq%20-%200%201&json=1

The response I got is:

```
{
  "status": "ok",
  "score": 8,
  "depth": 39,
  "pv": [
    "e2e4", "c7c5", "d2d4", "c5d4", "g1f3", "e7e5", "c2c3", "b8c6", "f1c4", "g8f6", "f3g5", "d7d5", "e4d5", "c6a5", "c4b5", "c8d7", "d1e2", "f8d6", "b2b4", "h7h6", "g5f3", "e8g8", "b4a5", "d4d3", "e2b2", "f6d5", "b1d2", "d7b5", "b2b5", "d5c3", "b5d3", "d6b4", "d3d8", "f8d8", "a5a6", "b7a6", "a2a3", "b4a5", "e1f1"
  ],
  "pvSAN": [
    "e4", "c5", "d4", "cxd4", "Nf3", "e5", "c3", "Nc6", "Bc4", "Nf6", "Ng5", "d5", "exd5", "Na5", "Bb5+", "Bd7", "Qe2", "Bd6", "b4", "h6", "Nf3", "O-O", "bxa5", "d3", "Qb2", "Nxd5", "Nbd2", "Bxb5", "Qxb5", "Nxc3", "Qxd3", "Bb4", "Qxd8", "Rfxd8", "a6", "bxa6", "a3", "Ba5", "Kf1"
  ]
}

```

# Answer
> 3 votes
I'm a bit late, but https://stockfish.online is a REST GET API for Stockfish. Make requests with a FEN string, depth, and mode. For example, making a GET request to `https://stockfish.online/api/stockfish.php?fen=r2q1rk1/ppp2ppp/3bbn2/3p4/8/1B1P4/PPP2PPP/RNB1QRK1 w - - 5 11&depth=13&mode=bestmove` would get the best move for the given FEN string at depth 13. Hope this helps!

# Answer
> 0 votes
https://chess-api.com/ \- it's basically Stockfish online.

Quite rich response data and WebSocket support. You pass FEN or moves.

---
Tags: engines, analysis, programming, evaluation, online
---


# Question
Title: Soundness and engine evaluation of the benko
Is the benko a sound gambit? Can I craft a "lifetime repertoire" around the benko? the engine disagrees but I have heard that the benko gives very long term compensation that may not be picked up on by our silicon friends.

# Answer
> 3 votes
In **most** lines of Benko black has sufficient counterplay. Sadly most is not all.

In particular the problematic line is inside the King walk variation: **1. d4 Nf6 2. c4 c5 3. d5 b5 4. cxb5 a6 5. bxa6 g6 6. Nc3 Bxa6 7. e4 Bxf1 8. Kxf1 d6 9. Nf3 Bg7 10. g3 O-O 11. Kg2 Nbd7 12. a4!**

White is planing to play **Nb5**, which practically shuts down black topical queenside play. Don't forget that white is still a pawn up. If black is very careful he may still draw, but winning is practically out of reach.

It's unlikely that black can find some improvement later in this line, so we have to look for alternatives at earlier point.

First approach that was tried in practice was trying to speed up development. Logic behind this approach goes like this: losing castling rights didn't really harm white (since he just "king-walked" to safety on g2), while it slightly delayed our development. So lets try delaying **Bxa6**, for example: **1. d4 Nf6 2. c4 c5 3. d5 b5 4. cxb5 a6 5. bxa6 g6 6. Nc3 Bg7 7. e4 O-O 8. Nf3 Qa5 9. Bd2 Bxa6** In practical play this is probably the best choice, since positions are still thematic. Just be aware that white has some advantage with accurate play.

Another approach is to go for very early **e6** pawn break. This approach is probably the soundest, but it sadly leads to positions that aren't exactly "Benko-like": **1. d4 Nf6 2. c4 c5 3. d5 b5 4. cxb5 a6 5. bxa6 e6 6. Nc3 exd5 7. Nxd5 Be7 8. Nxe7 Qxe7** As you can see position is a bit messy, but objectively close enough to draw. Problem with this approach is, that you are practically not playing Benko anymore. What's worse is, that you have to go for it so early, that you also evade Fianchetto and other variations, which you probably want to play against.

---
Tags: opening, benko-gambit
---


title: What e4 opening for an ELO below 1000?

text:
# Question
Title: What e4 opening for an ELO below 1000?
As a player with an ELO below 1000, what e4 opening would you recommend I focus on, the Italian game, Giuoco Piano or the Ruy Lopez?

# Answer
I agree with Brian that you should focus on as tactical openings as possible until you get to at least 1600. In general don't worry too much about the openings at this stage, tactics are for you right now much more important.

Focus on opening principles:

1. Control of the center (*e4*, *d4*, *e5*, *d5* squares)
2. Development of the pieces (as close to the center as safe)
3. Finding safe place for your king (castling)

However, I think that there are a lot of suitable lines for you in the Italian complex.

For example, **the Møller attack**:

**1. e4** you put a pawn in the center and open up lines for development of your light squared bishop and queen.

**1. ... e5** your opponent does the same.

**2. Nf3** you develop your knight and attack *e5*, gaining time.

**2. ... Nc6** your opponent develops his knight and at the same time defends *e5*.

**3. Bc4** you point your bishop at the weakest point in your opponent's camp - *f7*. This pawn is weak, since it's only protected by the king.

**3. ... Bc5** your opponent does the same. He can also try **3. ... Nf6**, the two knight defence, where older lines with **4. d4** will server you well.

**4. c3** you are preparing to play **d4**, aiming for total central control.

**4. ... Nf6** your opponent pressures your *e4* pawn and develops his knight.

**5. d4** you don't need to defend *e4*! Your development is good enough that your priority is opening up lines for attack. This comes with tempo on bishop.

**5. ... exd4** your opponent goes for few exchanges, aiming for **Nxe4**, winning a pawn.

**6. cxd4** preserving your center, renewing threat on bishop.

**6. ... Bb5+** your opponent moves bishop to safety with check.

**7. Nc3** but this doesn't harm your development, you develop your other knight, blocking the check.

**7. ... Nxe4** your opponent finally wins a pawn, but this losses time and your good development guarantees you good play in exchange.

**8. O-O** you break bishop pin, put your king to safety, and prepare **Re1**.

**8. ... Bxc3** your opponent tries to exchange a few pieces, thus lessening your attack.

**9. d5!** increasing tension in the center, gaining space, disorganizing your opponent pieces.
> 1 votes

# Answer
I agree with "none of the above" but I go further: Don't study openings yet.

If you start with 1. e4 there's the Sicilian, the Caro, the Petroff, and more, in addition to 1. ....e5. And, since you are under 1000, your opponents are probably also under 1000. You will be out of book very early and, whatever opening you play, you won't know what to do. It's true that it may be harder to figure out in "strategic" openings than "tactical" ones .... But that goes for your opponent too!

So, play. If you like the idea of (say) the Danish gambit (which I'd prefer to the King's gambit) then fine. Do that. But don't learn a lot of opening theory. Play games and go over them slowly using a computer and an opening data base (the one o chess dot com is fine for now). Ideally, go over them with a coach (but that can get expensive).

Learn tactical puzzles (tons of sources). Learn some strategic ideas, too. Strategy isn't just for masters! I don't like this notion that beginners should *just* do tactics. OK, your strategy won't be like Hikaru's. Nor will your tactics. At first, your strategy will stink, but so will your tactics. But good tactics often come from good positions.

I also suggest looking at the speed runs of really good players against beginners. I especially like Daniel (Danya) Naroditsky's speed runs. Of course he crushes beginners, but he explains what is going wrong in their games. I think this is more useful than studying games between GMs. Those guys are fighting over things that you and I may never understand but that's both tactical and strategic.

(Danya also posits that beginners and intermediates can play any opening, including the deepest.)

I also suggest not playing too much blitz and not playing bullet at all. Play slow games.
> 1 votes

# Answer
None of the above.

Much stronger players than you have little chance of understanding these mostly strategic openings. At just over 1800 FIDE I include myself in this.

At your level the biggest gains will come from improving your tactical play. The best openings for this would be the Kings Gambit against 1...e5 and the Morra Gambit against 1...c5. Concentrate on these two first.

You will have lots of quick wins with these openings (as well as lots of quick losses). Importantly, you will easily understand what happened, why you won or lost, and you will understand the basic idea - fast development aimed at the enemy king followed by checkmate. And the games will be fun. Ruy Lopez and Italian games will not be much fun.
> 0 votes

---
Tags: opening
---


title: Describing skill level

text:
# Question
Title: Describing skill level
I have a USCF rating of just over 1600 and in any given tournament that rating is usually just a bit short of the median rating of all players in the tournament.

However, the USCF website shows me as being the 84th percentile of players nationwide.

I'm thinking this discrepancy is probably due to the USCF sample including enormous numbers of scholastic players who play a few games and never again?

How might one characterize a 1600 rating to a non-chess player and where does it realistically rank against serious players, in terms of percentile?

# Answer
To a non-chess player, most chess players can be categorized into just a handful of levels:

* Masters
* Extremely Good Players
* Very Good Players
* Good Players
* Novices

To such a person, you would be considered a ***"Very Good Player"***. You will easily beat any "Novices" or people that are only competent at the basics of quality game play ("Good Players"). "Extremely Good Players" will be able to beat you most of the time, and "Masters" will be able to beat you all of the time.

Please note that I didn't simply make up these terms. I've listened to non-chess players talk about chess a fair amount, and these are the terms they typically use.
> 1 votes

# Answer
There are some rating distribution graphs in an answer to this question. One shows the distribution for only active players with established ratings. The shape seems to be a double bell curve, with one curve for scholastic and one for adults. The 1600-1699 range appears to be right around the peak of the "adult" bell curve, with more players there than anywhere else.

One interesting way of looking at it is what your expected win percentage would be against a master. A 600 point difference between 2200 and 1600 would indicate that you'd be expected to score about one point every 32 to 33 games. Or you could compare yourself against the currently highest rated player in the USCF, Fabiano Caruana, with a rating of 2879. A 1600 player would be expected to score one point every 1577 games against him.
> 0 votes

# Answer
In the old FIDE system, to my knowledge, a sort of informal classification was 1600-1800 = strong amateur 1800-2000 = low level expert (National masters or candidate masters) 2000-2200 = masters (FIDE masters and low IM) 2200-2400 = strong IM to weak GM 2500-2700 = Strong GM 2700+ = "Super" GM

In context of the general populus, you will beat most of the people around you
> 0 votes

---
Tags: rating
---


# Question
Title: What happens if my initial rating is below 1000?
If I were to play 5 FIDE rated games against players rated 1000 and I scored half a point in all of them;

1. Will my FIDE rating still be calculated but shown as unrated?
2. What happens if I play more games and my FIDE rating is still less than 1000?

# Answer
> 2 votes
FIDE rating floor was raised to 1400 on 1. March 2024.

If your first rating is under rating floor, or if your rating drops under 1400, you are unrated. Relevant parts of rating regulations:

> 7.1.4 A rating for a player new to the list shall be published when it is based on at least 5 games against rated opponents. This need not be met in one tournament. Results from other tournaments played within consecutive rating periods of not more than 26 months are pooled to obtain the initial rating. The rating must be at least 1400.

> 7.2.1 Players whose ratings drop below 1400 are shown as unrated on the next list. Thereafter they are treated in the same manner as any other unrated player.

So games will be used for calculation of your first rating, as long as they were played less than 26 months before you got rating, even if you performed under rating floor. As long as your performance stays under rating floor you won't get rated.

# Answer
> 0 votes
according to FIDE rules , if you have scored more than zero in a rated tournament , then your results will affect your FIDE rating even if it doesn't get published (as it is below 1000)

Hope this helps!

---
Tags: elo
---


# Question
Title: Has anyone looked at the percent of brilliant, best, book, etc moves in chess.com by rating?
After a game, chess.com lists moves as "brilliant", "best" etc down to "blunder". I'm wondering about the % of each for random selections of players at different levels is.

# Answer
Chess.com has a feature called Insights which allows you to view many statistics about a player(for different time controls) like their score vs various openings, win % during different times of the day/week, geography, tactics found/missed etc.

It also allows you to view the quality of a player's moves, including the number & percentage of brilliant, blunder, mistakes, inaccuracy and book moves.

**Note**: It's a paid feature of Chess.com. So, if you have a Diamond Membership on their platform, you can access this Insights feature for any user(they need to have a diamond membership for their account too!) on their platform. Some insights of top players/streamers(with a rating range of 3200 to 1100) are available which you can access for **free**.

Here's the number of brilliant moves from GM Hikaru's Insights:
> 3 votes

---
Tags: analysis, rating, statistics, blunder, chess.com
---


title: Can the king step into stalemate?

text:
# Question
Title: Can the king step into stalemate?
Is it possible that the king can move to a square, and the opponent can move, but no matter where it is a stalemate? If it is impossible, how do you prove that?

# Answer
If I understand what you are asking how about this

```
[Event ""]
[Site ""]
[Date "????.??.??"]
[Round ""]
[White ""]
[Black ""]
[Result "*"]
[FEN "6k1/8/3p4/2bPp3/1p1bP3/1Pp3p1/2P3P1/6Kn w - - 0 1"]

1.Kxh1 *

```

Black's last move was Nf2-h1+
> 28 votes

# Answer
Here is a variation on the answer of Ian Bush that I could see occuring in an actual game between (low-rated) human players. Of course, realistically White should have resigned long ago, but he plays on in hopes of a draw. Black has a mate in two, but because of time pressure decides to just push a pawn instead of looking for mating attacks...

```
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
[SetUp "1"]
[FEN "8/q4k2/8/p1b5/P2p4/6p1/6P1/6K1 b - - 0 1"]

1... d3+?? 2. Kh1!

```
> 31 votes

# Answer
On a similar beat to Ian Bush's answer, here is a chess problem that takes this idea to wacky proportions!

```
[Title "Christopher Jeremy Morse, EG 1984, White Stalemates Themselves In 4 Moves"]
[FEN "8/pp2r1q1/1p6/1pkr4/2p5/1pp5/nK6/1b6 w - - 0 1"]

   1. Ka3 b4+ 2. Ka4 b5+ 3. Ka5 b6+ 4. Ka6 Nc1 {Any move by Black is fine anyway, as all result in stalemating White!}

```

Source: The Die Schwalbe Chess Problem Databse
> 18 votes

# Answer
```
[Title "Black to move and draw"]
[FEN "6k1/7P/7K/6PP/8/8/8/8 b - - 0 1"]
[startflipped ""]

1... Kh8 {Kf8 and Kf7 would be blunders.} 2. Kg6 {Pawn to g6 is also legal, but both result in a stalemate.}

```

This position is only possible if the foremost pawn has just captured a piece (say, black's pawn).
> 14 votes

# Answer
It might also be worth pointing out that if you make a move after which any move by your opponent would lead to stalemate, the game finishes immediately. See FIDE's Laws of Chess, Article 9.6:

> The game is drawn when a position is reached from which a checkmate cannot occur by any possible series of legal moves. This immediately ends the game, provided that the move producing this position was legal.

Thus, from a technical point of view, some of the answers to this questions are slightly wrong. The game is not ended by stalemate (article 5.2) but by the article above.

The only (admittedly, very conceived) practical relevance that I can think of is that without the rule above, after playing Ka3 in Rewan Demontay's example, you could resign and hence lose the game. But you cannot resign as the game has already finished. (Note that even without Article 9.6, you still would not be able to lose on time, that is covered (redundantly?) by Article 6.9.)
> 5 votes

# Answer
## Another simpler variation on the theme

```
[FEN "8/b1p5/1B6/k7/8/6p1/6P1/6K1 w - - 0 1"]

```

Here, white has just captured something on b6 with the bishop. After black recaptures with the bishop, Kh1 is irreversibly stalemate.
> 1 votes

---
Tags: stalemate
---


# Question
Title: What is going on with FIDE Federation "NON FEDERATION"?
In the latest FIDE rating list the former USA players Alejandro Ramirez and Timur Gareyev have their federation listed as "NON FEDERATION". I understand they have both faced accusations of sexual misconduct but I'm puzzled as to how their federation changed from "USA" to "NON". Anybody know what is going on here?

# Answer
According to this document from the USCF, the USCF membership of both of these players has been permanently revoked by the Executive Board. Since they are no longer members of the USCF, they can't play under USA.
> 6 votes

---
Tags: fide, uscf
---


title: dealing with the pirc

text:
# Question
Title: dealing with the pirc
What are some aggressive lines that I can employ against the Pirc, I have been using the 150 attack but I don't like black's Queenside play with c6,b5 and want an alternative setup that allows me to play aggressively.

# Answer
As both a Pirc and a `1. e4` player here's a few thoughts, basically my comments expanded.

Firstly you have to understand the Pirc is a counter attacking system, "defence" is in many ways a misnomer. Black deliberately accepts a slightly cramped position in the hope that he/she can gain counter-play by seeing where White places his or her pieces and reacting appropriately - gaining this counter-play is at the very heart of Black's strategy. So as White you have two main choices

1. Be aggressive and crush black before the counter-play starts (As a Pirc or Modern player you have to accept that *very* occasionally this will happen). Typical systems here are the Austrian Attack, the Argentine Attack, the 150 Attack, the Bg5 (aka Byrne) system and the Bc4 (aka Kohlmov) system, and a number of unsubtle variations involving a very early `g4` or `h4`
2. Concentrate on minimising the counter-play and only once Black is strangled start your own more direct plans. Typical here are the Classical Variation and the Fianchetto Variation, though some ways of playing the 150 attack can tend towards this.

These are of course extremes, and there is a whole spectrum in between. But the point is if Black plays accurately he/she will get counter-play and all you can control is the degree of it - and if you spend more of your time with your plans rather than stopping Black's, then Black will get more time to progress this counter-play. And if your play is on the king side, as is typical then Black's counter-play will be where you don't have your pieces, i.e. on the queen side or in the centre.

So if you don't like the counter-play, play the Fianchetto system or the Classical System - Karpov played them for a reason

If you want to be aggressive you have to accept Black will get counter play. You can split the aggressive systems roughly in two, those where White plays in the centre, such as in the Austrian, the Bg5 variation and the Bc4 variation, and where black plays on the king side, such as the Argentine attack or the 150 attack. In the central systems you are trying to push `e5` and `e6` if possible and crush black. `f4` in the Austrian is the obvious supporting move, Bg5 aims at making `e5` more difficult for Black so making it easier for White due to the latent attack against the Black Queen, and Bc4 aims at supporting the pawn into e6 quickly after it has reached e5. Each has their own features

The Austrian Attack

```
[White "Austrian Attack"]
[Black "Pirc hero"]
[StartPly "9"]
[FEN ""]

1. e4 d6 2. d4 Nf6 3. Nc3 g6 4. f4 Bg7 5. Nf3

```

is a very good system for White. Despite repeated comments here the Pirc is sound (good enough Nepo for Mamedyarov, good enough for me) and if Black knows what they are doing you won't blast him/her off the board, but IMO this is about the best bet. There are two main problems, one practical, one theoretical. The practical one is there is a lot of theory here, and Black is likely to be booked up. Further there are two big main variations ( `5. ... O-O` and `5. ... c5`) which are very different in nature, and especially the `c5` can get to insane positions where you have to know what you are doing .The theoretical one is your poor black squared bishop - that f pawn has condemned it to being a spectator for a while, and if Black knows what they are doing it will stay that way. But IMO if there is any variation that really tests the Pirc it's the Austrian attack.

The Bg5 (Byrne) Variation

```
    [White "4 Bg5"]
    [Black "Pirc hero"]
    [StartPly "7"]
    [FEN ""]

1. e4 d6 2. d4 Nf6 3. Nc3 g6 4. Bg5

```

is also good. As I stated earlier White hopes to use the bishop to strengthen the `e5` break, and as White also often plays `f4` there is some similarity to the Austrian Attack - in fact one can almost think of this variation (after White plays `f4`) as an attempt by White to play the Austrian Attack *without* getting a bad dark squared bishop. In fact for a while this was the line I feared most as a Black player, but the problem is black doesn't have to play `4. ... Bg7`, instead `4. ... c6` starts to set up the standard Queen side counter play which you want to avoid. And in this variation the Bg5 variation tends to move from a "central attack" variation to a "king side attack" variation with an strong (if you are white) / exposed (if you are black) bishop on g5 - it can get hit not only by h6, but f6 and also Ne4; for this reason the d5 break by Black is more common in this variation than most. But it is a good variation.

The Bc4 Variations

```
    [White "4 Bc4"]
    [Black "Pirc hero"]
    [StartPly "7"]
    [FEN ""]

1. e4 d6 2. d4 Nf6 3. Nc3 g6 4. Bc4 Bg7 5. Qe2

```

I wouldn't recommend. `5. Qe2` is typical and thematic here as white is trying to get e4-e5-e6 in as quickly as possible. The problem is it just doesn't quite work, and often leave White with an exposed (or no) white squared bishop, on c4 it just encourages `b5`, `Na5`, `Nd7-b6`, `d5`. Further white weakens the already weak d pawn - in fact black can attack it straight away with `5. ... Nc6` and while complicated that line is probably better for black. And that's supported by the stats in the Lichess Master's database:

where White really isn't doing that well.

I'll try to find time and energy come back and look at the more king side variations - but as you effectively say you don't want to face the q side play I for the moment am going to rule those out for now.

In summary if you want aggressive I would say play the Austrian Attack if you want to put some effort into it, 4. Bg5 if not.

(And there's always the Grand Prix Attack...)
> 2 votes

---
Tags: repertoire, pirc-defense
---


# Question
Title: Purpose of these (potential) pawn breaks in Gukesh - Ding Liren (Tata Steel 2024)
I'm watching an old stream of this year's Tata Steel round 3. In the game Gukesh - Ding Liren, at the following position

```
r1b2rk1/1pp1qp2/1bnp3p/pN2p1pn/P1B1P3/1QPP1NB1/1P3PPP/2KR3R w - - 4 14

```

the commentators, a GM and a IM, say that White's plan or goal move would be d4, while Black's would be (after proper preparation) ...f5. The engine agrees with them, and Gukesh played d4. What's the point of these moves? To me, that'd be weakening each king's own defensive structure, and if I was playing this game, I would want to push the kingside pawns as White, and the queenside pawns as Black.

# Answer
> 1 votes
Thank you for sharing this very interesting position and question.

King is only unsafe if it can be attacked - in this case, while both kings look a bit airy, they aren't in real danger.

White doesn't have enough pieces on the kingside for pure piece attack and he also cannot go for a pawnstorm, since his pieces are in way of his pawns. If he tries, for example with **1. h4 g4!** takes all dreams of attack away and gives black a good advantage after **2. Ne1 Kh8 3. Nc2 f5 4. exf5 Bxf5** with **Nxg3** to follow. After smoke clears center is opening up, black has very good bishops and rook on open f-file with clear advantage.

Likewise black cannot dream of queenside attack. His pawns are blocked by his own pieces, his queen is on the wrong side of the pawn chain, so it cannot join his queenside attack. Here it's hard to even find a candidate move on the queenside.

So let's look at the center. Since it's not totally fixed, play in center is still possible. Here we see this typical asymmetry in Italian opening complex: white is ready to play **d4**, while black cannot organize **d5**, since his knight is slightly misplaced on *c6*. So **d4** is viable candidate move for white. Additionally it's clear white has complete control of *d4* square - both of his knights and his rook are covering it. Because of this pawn break will release the power of all these pieces.

On the other hand black has more space on the kingside, so his hope for counterplay lies there - with eventual **f5**. This comes with threat of **f4**, trapping white dark squared bishop. If white has to take on *f5*, then black takes back with his light squared bishop, thus putting it on a very nice diagonal.

These abstract considerations don't matter, unless variations can make use of them. So let's look at few lines.

First let's check if **d4** is even safe to play - let's not forget *e4* is hanging: **1. d4 exd4 2. Nfxd4 Nxd4 (2. ... Qxe4 3. Nxd6!! +--, 2. ... Ne5! +=) 3. Nxd4 Bxd4 4. Rxd4** with small advantage for white due to better development and more space due to *e4* (which can be later supported with **f3**).

Next thing we have to check is, if black can prepare **f5** in response to **d4**: **1. d4 Kg7 2. Rhe1 (2. Kb1?** if white makes empty move **f5!? 3. exf5 Bxf5 3. Ka1 Nxg3 =)** protecting *e4*, and now we get crazy complications, which according to engine prefer white, after **2. ... f5?! 3. dxe5 f4 4. exd6 cxd6 5. Nxd6 Ba7 6. e5 fxg3 7. fxg3 +-**. White has crazy good attack in exchange for piece, since center opened up and his pieces are ready to take advantage of now very unsafe black king.

However, in the game Ding Liren found a safe way to win the *e4* pawn: **1. d4 exd4 2. Nbxd4 g4 3. Nh4 Bxd4 4. cxd4 Qxe4**. White has sufficient compensation, but no more than that.

---
Tags: strategy, pawns, pawn-structure
---


title: Skill degradation

text:
# Question
Title: Skill degradation
I am 27 years old and have been playing chess since December 2020. I won a semi-rapid (25+5) tournament under 1500 FQE (chess federation in Quebec) 6 months ago.

I took a break from November 2023 to February 25th, 2024. I was rated 1970 rapid on chess.com in November. Now I started playing and I lost like 150 Elo.

I spend so much time calculating moves, I am not as sharp in tactics and sometimes I just blunder a piece in one move. I am feeling quite discouraged.

Do you have some recommendations to come back to the old strength and even push to 2000–2100?

# Answer
During the epidemic I didn't play for 2-3 years. Before I stopped I had Lichess blitz rating around 2000, after I resumed my rating fell to 1600. Mostly due to missing simple 1 or 2 ply tactics.

To regain my old rating (and improve it) I needed roughly half a year. It's way easier to regain playing strength than to get it first time, since you already got it once and so have some clue what you need to do to get it back.

Tactical vision is like a muscle, that gets a bit weaker if not used. Just like muscle, you can get it back very quickly with some exercise. Just do a lot of tactics for few weeks and you will play better than even before. I think that taking longish breaks is even beneficial for improvement in long run.
> 10 votes

# Answer
You really don't give us much to work with. What time limit are you playing at? Are these OTB or online? A technique recommended to avoid blunders OTB used to be to write the move down before making it, but this is now frowned upon. However, the principle is still a good one. Play with a rhythm that changes from calculating to checking. Online, move the mouse and hover for a few seconds before releasing it.

If you spend a long time on tactics but are not very good at them, perhaps you are playing the wrong openings. Consider how you you can force the opponent into playing your kind of game
> 1 votes

---
Tags: rating, elo, development
---


title: Why is Ng3+ brilliant?

text:
# Question
Title: Why is Ng3+ brilliant?
Why is the move Ng3+ brilliant?

```
1kb4r/2q2p2/pp4r1/2bPp3/2p1P2p/2P2Qn1/P1B2NPP/2B1RR1K w k - 0 1

```

# Answer
White only has three possible moves here.

Qxg3 is obviously bad.

After Kg1, Black could just play Nxf1 with a sizable advantage - but there's actually a better follow-up. Bg4 traps the queen since the f2 knight is now pinned.

And after hxg3, the recapture hxg3+ will win the knight back and more.

```
[FEN "1kb4r/2q2p2/pp4r1/2bPp3/2p1P2p/2P2Qn1/P1B2NPP/2B1RR1K w - - 0 1"]

1. hxg3 (1. Kg1 Bg4 (1... Nxf1 2. Kxf1)) 1... hxg3+ 2. Kg1 (2. Nh3 Bxh3 3. Be3 (3. gxh3 Rxh3+ 4. Kg2 Rh2#) 3... Bg4+ 4. Kg1 Bxf3) 2... gxf2+ 3. Rxf2

```
> 6 votes

---
Tags: analysis, tactics
---


# Question
Title: Alapin Sicilian 4th move after 2... Nf6 3.e5 Nd5
```
[FEN ""]
1.e4 c5 2.c3 Nf6 3.e5 Nd5

```

According to some databases I have looked at 4. Nf3 is clearly better than 4. d4. Actually d4 loses more than it wins. For example the lichess.org masters databases scores 4. d4 as 26/43/31 (%wins / %draws / %losses), in contrast to the score of 29/48/23 for 4. Nf3. If I understand it right, there could be some weaker move down the main line after 4. d4 that is responsible for this, but I couldn't find one. It looks like d4 really is not so good for white. Does it mean that 4. Nf3 will gradually become the main line?

# Answer
> 2 votes
If you measure by the Lichess masters database, this is already happening:

Nf3 has been more popular than d4 since 2019.

---
Tags: sicilian-defense
---


title: Table bases: an endgame challenge

text:
# Question
Title: Table bases: an endgame challenge
From where can I download this "data/syzygy/regular" file so that the code below becomes functional ?

```
import chess

import chess.syzygy

with chess.syzygy.open_tablebase("data/syzygy/regular") as tablebase:

    board = chess.Board("8/2K5/4B3/3N4/8/8/4k3/8 b - - 0 1")

    print(tablebase.probe_wdl(board))

```

> -2

# Answer
> 5 votes
You can download the tablebases from the Syzygy website.

---
Tags: engines, tablebases
---


# Question
Title: Why is this the correct answer to chesspuzzle.net puzzle 37161?
https://chesspuzzle.net/Puzzle/37161

```
[FEN "r4rk1/2p2n1q/1p1b4/3Pp3/2Q2pP1/P1N1B2P/1P4P1/2RR2K1 w - - 0 1"]

1. Ne4

```

The answer given is Ne4, which is followed by the pawn on f4 capturing the bishop on e3, at which point white is able to fork black's king and queen, however this is entirely avoidable by black simply moving either the king or queen to a square that prevents the fork from happening, e.g. Qh6. So why is Ne4 a better solution to this puzzle than simply moving the bishop to a safe square, e.g. d2?

# Answer
> 2 votes
You're absolutely right. Black can avoid the King + Queen fork by playing Qh6 instead of fxe3. But the reason why Ne4 is better than Bd2 is because it centralises the knight and prevents Black from bringing their Knight to g5. What does Ng5 do? First, Black threatens to sac the knight on h3 for two/three pawns and weaken the white king. Second, it prevents white from going to Ne4.

Having a knight on e4 definitely gives white an upper edge over black and makes it difficult for Black to create plans.

---
Tags: analysis, tactics, puzzles
---


title: How to sense the 0.5 difference

text:
# Question
Title: How to sense the 0.5 difference
In the below opening, after 10. O-O-O, the best move for black is 10... Re8, this is understandable, to control the half-open file; however, 10... Qd7 is also following the principle -- to connect the rooks, but unfortunately SmallFish shows this loses about 0.5, or 50 centipawn.

How could one be able to sense the 50 centipawn? It seems "just follow opening principles" does not work any more to such subtle distinction. How could one tell the difference? Is there some deduction, calculation, or methodology would help?

```
[FEN ""]

1. b3 e5 2. Bb2 Nc6 3. e3 Nf6 4. Bb5 d6 5. d4 exd4 6. Qxd4 Bd7 7. Bxc6 Bxc6 8. Nf3 Be7 9. Nc3 O-O 10. O-O-O

```

# Answer
50 centipawn difference may mean a lot in some positions and practically nothing in other ones.

In this particular position though, it's pretty clear that **Re8** is an useful move, as you pointed out, it takes control of *e-file*. On the other hand it's hard to say what **Qd7** actually accomplishes. True, it connects the rooks - but is this really important in this position? On the other hand it cuts off bishop retreat and queen on *d7* just feels very awkward, a bit too exposed if you want. *d8* may even be better square for her than *d7*.

Opening principles still matter of course, even if this position has more of middlegame character. Here however, you have a conflict between two principles: connecting the rooks and putting a rook on open file. So the question is which is more important there, which you have to decide both by calculation and by asking yourself, what move actually does, not just which principle it follows.
> 2 votes

---
Tags: opening
---


title: Decent e4 e5 opening for white

text:
# Question
Title: Decent e4 e5 opening for white
I'm seeking guidance from an experienced e4 player. Currently rated 1950 on Chess.com Rapid, I find myself struggling to reach positions that suit my style. Despite having played the Vienna Gambit for a few months, opponents increasingly respond with Nc6 followed by Nf6, resulting in rather dull positional games. I'm drawn to dynamic, imbalanced positions and crave sharper, tactical encounters.

Could you kindly suggest openings that present significant challenges for Black and lead to the type of play I enjoy?

# Answer
> 3 votes
I would recommend you sharper lines of Italian opening complex. These positions you can reach through two different move orders:

* 1. e4 e5 2. Nf3, where you have to face Petroff, but you have wider choice against two knight defence;
* 1. e4 e5 2. Bc4, where you don't have to face Petroff, but you have to commit to gambit lines against two knight defence.

# 1. e4 e5 2. Nf3

Here black has two dubious gambits (Latvian with **2. ... f5** and Elephant with **2. ... d5**). Both promise advantage and sharp play, so no problem. Just don't forget to prepare something against them.

Phillidor with **2. ... d6** leads to sharp play in practically all mainlines.

Petroff mainline is a bit stodgy, however you have alternative option in just as good and sharper **1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. Nc3 Nxc3 6. dxc3**. Your plan is to castle long and start a kingside pawnstorm. Doubled c-pawns are advantageous, since they provide extra cover for your king on the queenside.

# 1. e4 e5 2. Bc4

Here black has two independent options, practically everything else transposes to Italian complex.

First is **1. e4 e5 2. Bc4 c6 3. Nf3 d5 4. Bb3 Nf6 5. d3 Bd6 6. Nc3**. If black decides to close the center with **6. ... d4 7. Ne2** you are doing perfectlly well. Knight will go to *g3*, and later you can reroute your *f3* knight to *h4*, so both will point to *f5*, which is a classical motif in kingside attacks. So mainline is for black to open the center with **6. ... dxe4** with open position and concrete play.

Second is the most popular **1. e4 e5 2. Bc4 Nf6**. Now you have a choice between quiet **3. d3**, which usually transposes to calmer lines of Italian complex, and **3. d4** \- let's focus on this one:

* **1. e4 e5 2. Bc4 Nf6 3. d4 Nxe4?? 4. dxe5** promises decisive advantage in all lines, but requires some preparation;
* **1. e4 e5 2. Bc4 Nf6 3. d4 Nc6 4. Nf3 exd4** transposes to open variation of two knight defense;
* **1. e4 e5 2. Bc4 Nf6 3. d4 exd4 4. Nf3 Nxe4 5. Qxd4** is Urusov gambit, which is at least equal in all lines and very sharp (if black plays **4. ... Nc6**, you transposed to open two knight defense again). In Urusov gambit your plan is to castle long, play **Nc3** and **Bg5** and sac this bishop on *h6* anytime black plays **h6** after **O-O**. Exchange sac on for bishop on *e6* is also common motif. Just a single line for a taste: **1. e4 e5 2. Bc4 Nf6 3. d4 exd4 4. Nf3 Nxe4 5. Qxd4 Nf6 6. Nc3 Be7 7. Bg5 c6 8. O-O-O d5 9. Rhe1 Be6 10. Qh4 O-O 11. Bd3 h6 12. Bxh6 Ne4 13. Qh5**

# Two knight defense

In both move orders you can reach two knight defense. For example, through:

* **1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6**
* **1. e4 e5 2. Bc4 Nf6 3. d4 Nc6 4. Nf3**

If you used the first move order, you have choice between lines with **4. Ng5** and **4. d4**, while with second move order you had to commit to lines with **d4**. Both are sharp, difference being that in **4. Ng5** mainline black sacs a pawn for activity, while in **4. d4** white sacs a pawn for activity.

After **1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. d4 exd4** you have choice between three lines:

* **5. Ng5?!** the Perreux variation, which is sharp but more than a bit dubious.
* **5. O-O** will lead to either Max-Lange (**5. ... Bc5**) or to Double Scotch gambit (**5. ... Nxe4**). Both lines are very sharp, but if black has good preparation will petter out to quick draw.
* **5. e5** is the advance variation of the Scotch gambit. It leads to complex double edged positions, but less sharp than other two options. For a taste: **1. e4 e5 2. Bc4 Nf6 3. d4 exd4 4. Nf3 Nc6 5. e5 d5 6. Bb5 Ne4 7. Nxd4 Bd7 8. Bxc6 bxc6 9. O-O Bc5 10. f3 Ng5 11. f4 Ne4 12. Be3**

# Sharp lines in Italian

Italian can be played quietly with **d3**, but there are some sharp options:

* **1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. b4**, the Evans gambit, which Peter mentions in his answer, is still very playable.
* **1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. c3 Nf6 5. d4 exd4 6. cxd4 Bb4+ 7. Nc3 Nxe4 8. O-O Bxc3 9. d5**, the Møller attack, is the sharpest option. As usual with sharp lines, if black is well prepared it will be a quick draw.
* **1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. c3 Nf6 5. d4 exd4 6. e5** is very topical at super-GM level for last few years. Line bears some similarity to advance variation of scotch gambit and is as complex and double edged as the gambit. Black can quickly go astray, as for example in **1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. c3 Nf6 5. d4 exd4 6. e5 d5 7. Bb5 Ne4 8. cxd4 Bb6 9. Nc3 O-O 10. Be3 Bg4 11. h3 Bxf3 12. gxf3 Nxc3 13. bxc3** where white gets a very strong kingside attack based on open *g-file*.

# Answer
> 0 votes
After 1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 there is always the Evans' Gambit. With best play, Black can get equality, but it's easy for Black to go astray.

Against the Petroff/Russian defense, the Cochrane Gambit is playable: 1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nxf7

I don't know about an aggressive line against the Philidor, but that's pretty uncommon at your rating anyway. White gets a good game in the main lines.

---
Tags: opening, tactics, 1.e4, attack
---


# Question
Title: Are there chess variants than involve only cooperation and no competition?
One thing I've noticed is that even the most unusual chess variants tend to involve some sort of a competition. For instance in 4 player chess teams the members of the same team cooperate with each other, however the different teams still compete against each other. In some variants the game is something other than to trap the King, but in the ones I've read about and played it's still a competition with a winner and loser, or a draw.

My question is are there any variants that involve all the players cooperating to achieve a common goal, with all players either winning together or losing together as opposed to competing with each other?

# Answer
There are helpmate problems. I haven't seen many of these recently, but they involve both sides cooperating to get to mate.

But very few games of any sort involve only cooperation. The only one I can think of, offhand, is SimCity and, even for that, some of the variations are competitions against the computer or against your own previous score.

Games more or less have to be competitive to be interesting, even if the competition is very light-hearted.
> 2 votes

# Answer
I do not think such a chess variant exists. But it would be possible to design one that works well without too much effort, I think. I would start with Horde chess, make the defender's army smaller, split it up into two parts (controlled by Black and White on alternating turns), and let the movements of the Horde pieces be controlled by throwing dice (maybe with captures compulsory).

There is then certainly some material imbalance where the task of the defending players becomes difficult; whether it becomes interesting, I don't know. But I would feel optimistic that something along these lines could be made to work well after some tinkering with the details.
> 0 votes

---
Tags: chess-variants
---


title: Three bishops vs. rook endgame

text:
# Question
Title: Three bishops vs. rook endgame
Can a rook force a draw against three bishops?

One of the bishops is on a different coloured square than the other two.

# Answer
It's generally a win for the three bishops. However, it can be a rather long process.

The tablebase I consulted says that in this position with White to move, the best move for White is Kd3, which is a win for Black with DTZ of 87.

```
[FEN "8/2kb4/8/8/8/2K1b2b/8/3R4 w - - 4 3"]

```

In fact, in some positions, the 50 move rule will trigger, which could result in a draw with best play. Here, Kd5 results in a DTZ of 101:

```
[FEN "k7/3b4/8/8/2K5/7b/5b2/1R6 w - - 1 1"]

```
> 1 votes

---
Tags: endgame, bishop-endgame, rook-and-minor-endgame
---


# Question
Title: When can legions of knights on an infinite chessboard checkmate a lone king?
On an infinite (perhaps only in one direction?) chessboard, what kind of configuration of (possibly a very large number of) knights could checkmate a lone king? I'm really thinking of an infinite-in-two-directions chessboard... And the salient point in my mind is that, although an individual knight can move faster than a king, a larger group of knights cannot. So, for example, it seems to me that an infinite line of knights could not checkmate a king that was (what number?) a few squares away from that line.

I'm quite curious as to whether there's a conceptual way to quantify this.

# Answer
If the king is at least three squares away from the infinite east-west line of knights then imagine the king starts running away to the north. At some point, after making n moves the king must be prevented from moving north by having all three squares to the north blocked. This will require at least two knights which would have to have made about 2\*n/2 = n moves.

But in this case, the king can capture one of the knights instead. So there must be three knights moving north instead, which would take about 3\*n/2 \> n moves, so the king can outrun them.

The sacrifice of the knight is never advantageous for the pursuers because it’s cost about n/2 moves for the sacrificial knight to move up but it only cost 2 moves for the king to eat it.

So the king cannot be captured even by an infinite line of knights.
> 15 votes

# Answer
It's in theory possible if the king starts right next to the knights. I guess that means the "number" is 1.

```
[fen "8/8/8/3k4/2NNN3/3N1N2/3N4/4K3 w - - 0 1"]

1. Nb4#

```
> 3 votes

---
Tags: analysis, knights, mathematics
---