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20 votes
Accepted

What's the maximum amount of material that a puzzle with unique solution can have?

This must be the maximum for an illegal position (adapted from David's attempt): [Title "_David_, v. NDE: White to move and win"] [FEN "qqqqqqqq/qkqQqqqq/qqqQqqqq/qQQQqqqq/qqqqQqqq/...
Noam D. Elkies's user avatar
13 votes

The 50 moves game

I have managed 106 single moves (see below). As OP notes, if 12 pawns promote, capturing the other 4 pawns, then all captures by officers must be on 1st/8th ranks. So that would be 88+26=114. Can this ...
Laska's user avatar
  • 12.1k
10 votes

Most mate options after 6 moves

11 without discovered checks: [FEN ""] [startply "12"] 1. e3 e6 2. d4 Ke7 3. Bc4 Kf6 4. Nh3 Kf5 5. Bxe6+ Ke4 6. Qh5 Qe8
Noam D. Elkies's user avatar
8 votes

Most mate options after 6 moves

5.5 moves to 14 fool's mates: [FEN ""] [startply "11"] 1. b4 e6 2. Bb2 Qh4 3. Bxg7 Ne7 4. Bb2 Rg8 5. g3 Rxg3 6. f4 For 6.0 moves, start with something like 1. a3 and then reverse ...
Noam D. Elkies's user avatar
7 votes

What's the maximum amount of material that a puzzle with unique solution can have?

There's no reason you can't have all the material on the board with all pawns promoted to queens, for maximum material. For example: White to move, mate in 1, everything but the mating move loses. [...
D M's user avatar
  • 19.7k
5 votes
Accepted

Fastest from a complete beginner to FIDE 2200?

The first thing to note is that there is no reliable record of when players first learn the moves. The closest we have to this is when they get their first FIDE rating and even with that there are ...
Brian Towers's user avatar
  • 98.3k
4 votes
Accepted

What is the longest string of moves by one side on one color of the board?

Thanks to this CQLi query: cql(input Mega_Database_2023.pgn) flipcolor { sort "Consecutive" line singlecolor 18 1000 nestban --> move to light . * } // check 3-fold repetition: ...
double-beep's user avatar
  • 4,350
4 votes

The 50 moves game

An excellent question which I've no idea of the answer to. To illustrate the difficulties, however, here's a very cursory attempt which only manages to get to 81 half moves. [FEN ""] 1. d3 ...
John Chernoff's user avatar
3 votes

Most mate options after 6 moves

I bid 7. [FEN ""] [startply "12"] 1. e4 f6 2. Qf3 Kf7 3. Be2 Kg6 4. e5 Kg5 5. d4+ Kh4 6. d5 e6
Rewan Demontay's user avatar
3 votes

Longest *fairy* chess problem

Is there a clear definition of what constitutes a "fairy" problem? For instance, if you can stipulate a change to the dimensions of the board, then solutions of an infinite length could be ...
John Chernoff's user avatar
3 votes

Max percentage of mating pieces

It's easy to get 16/17 = 94.1% [FEN "4B3/4Q3/3QQQ2/1N2B2N/4k3/1Q5Q/3PKP2/2R1Q1R1 w - - 0 1"] On further thought that's not legal for lack of a previous Black move. This should be fixable, ...
Noam D. Elkies's user avatar
3 votes
Accepted

What position has the most possible moves that all lead to being checkmated?

I bid 200 moves, with two moves added courtesy of an improvement by @James Martin. R4Q2/2Q4Q/4Q3/1Q4QB/3Q3b/Q4R1q/2Q1rprN/2nbBKNk w - - 0 1
Rewan Demontay's user avatar
3 votes

Challenge: Create the longest game determined only by the final diagram and move number

In 2023, a new proof game tool exploded into the arena: Stelvio by Reto Aschwanden has broken the record for the longest published proof game to be fully tested. The new record is 48.0 moves! [Title &...
Laska's user avatar
  • 12.1k
2 votes

What is the fastest possible stalemate by castling?

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
Lucenaposition's user avatar
2 votes

What position has the most possible moves that all lead to being checkmated?

I only write this as an answer (it isn't) as this is an invaluable source for one-move records, with citations (surely more questions on CSE apply). Since the positions are rather old some records ...
Hauke Reddmann's user avatar
2 votes

Most delaying moves before checkmate

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 &...
Rewan Demontay's user avatar
2 votes
Accepted

How often can the initial position be repeated under FIDE tournament rules?

You appear to ask several different questions, so I will answer your headline question: How often can the initial position be repeated under FIDE tournament rules? You give a very big clue to the ...
Brian Towers's user avatar
  • 98.3k
2 votes
Accepted

Most mate options after 6 moves

15: [FEN ""] 1. e3 f6 2. a4 Kf7 3. a5 Kg6 4. Ra4 Kf5 5. Bc4 Ke4 6. Qh5 Qe8 There are 11. discovered check mates plus 7. Qd5# 7. d3# 7. f3# and 7. Nc3#
Albert.Lang's user avatar
1 vote

Are all moves or types of moves (see details) in chess possible?

Since no one has answered yet, I will try some simple analysis first. Let's first make sure all vanilla moves/move types are possible without considering ways for the game to end. In the data, all ...
alices_and_bobs's user avatar
1 vote

Longest checkmates with the biggest material disadvantages in "open" positions?

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/...
Rewan Demontay's user avatar
1 vote

Longest *fairy* chess problem

On request, here is the problem: SCHWALBE 324-2, Article "Die Valladao-Challenge" by Jochen Schröder, p.389, Nr. 5, by Jochen Schröder, help-aim square h8, 2+59, in 720575940379279357 moves, ...
Hauke Reddmann's user avatar

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