# Tag Info

Accepted

### Maximum number of pieces on board in dead position

EDIT 30-Dec-2023: added the R(1,D) position with 32 units. So Challenge 1 is now completely resolved. Apologies that the first few lines are a bit theoretical. I reach the actual chess as soon as I ...
• 12.1k
Accepted

### Does 'dead position' consider the 75 moves rule?

In section 3.10.1, the laws define what legal moves are: 3.10.1 A move is legal when all the relevant requirements of Articles 3.1 – 3.9 have been fulfilled. The mentioned sections 3.1 to 3.9 only ...
Accepted

### What will happen if you have a position where no one can lose?

I was wondering the outcome for a standard format chess game will it be draw because no one can win. According to the FIDE Laws of Chess: 5.2.2 The game is drawn when a position has arisen in which ...
• 98k

### Is the dead position problem solvable?

Computer detection of dead positions is much trickier than people think. It is unlikely that an algorithm exists that runs in reasonable time and is 100% accurate. It is easy to check for a simple ...
• 5,040

### Maximum number of pieces on board in dead position

I've come up with 23, in the following position, with promotions: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] [FEN "nb2k3/2p5/1pP5/1Pp5/2P1p1p1/3pPpPp/...
• 4,196
Accepted

### Why does this game not end as a draw by insufficient material?

Why this game does not end immediately as a draw by insufficient material? Two reasons. There is no rule regarding ‘insufficient material’. What there is is a draw due to a ‘dead position’. This is ...
• 98k
Accepted

I am not sure if this is exactly what you are asking for, but here is a try. [FEN "8/8/8/2p1p1p1/2P1PkP1/4Q1RB/3PPpPp/3n1Kbr b - - 0 1"] [startflipped ""] 1... Nxe3+ 2.dxe3+ {2....
• 16.1k
Accepted

### When checkmate is impossible in a position

What you're asking goes by the name of "Dead Reckoning" in the domain of problems and retro problems. (1) There isn't an algorithm I know of except the one mentioned by zaifrun: brute force. The ...
• 5,040

### Maximum number of pieces on board in dead position

Funny task. I think I'm still pretty far from the maximum, but here is a suggestion with 23 men: [Event "?"] [title "Challenge 3, 23 units"] [FEN "NRN1k1bn/QRKpPp2/PPpP1Pp1/2P3Pp/7P/8/7B/8 w - - 0 ...
• 16.1k
Accepted

### What happens if me and my opponent only have kings?

Since you can't move your king into check, you can't legally check the other king. The Laws of Chess, section 5.2b, states that: The game is drawn when a position has arisen in which neither ...
• 216
Accepted

### Longest "death certificate"

Here is such a position. [FEN "1k6/p1p1p1p1/P1P1P1P1/8/8/8/PKP1P1P1/8 b - - 0 1"] [startlfipped ""] With Black to move, no side can make any progress. White still has plenty of ...
• 6,192

### Is the dead position problem solvable?

Miguel Ambrona’s CHA solver “Chess Unwinnability Analyzer” (GitHub repo, white paper) is an efficient solution to this problem. It uses an incomplete algorithm to analyse positions and determine ...
• 171

### How long can a player hold off a draw by the 50-move rule?

The answer is trivially the starting position - [fen ""] This exact question hasn't been asked before (I think) but it has been answered here. Here is the relevant part of that answer - ...
• 98k

### Why does this game not end as a draw by insufficient material?

A bit late, but Miguel Ambrona recently developed an algorithm to assess whether a given position is a draw, or loss on timeout, under FIDE rules—in short, whether a checkmate is at all possible. ...
• 151

### Is the dead position problem solvable?

I would expect that it is a good bit easier to write a program that is good at detecting dead positions than to write a program that plays chess well. A simple strategy may be to play out a large ...
• 782
Accepted

### How long can a player hold off a draw by the 50-move rule?

I interpret the following White will play as long as possible, and not want to lose. Black will claim a draw as soon as possible, if not win as meaning that Black does not help (i.e., Black tries to ...
• 871

### Does 'dead position' consider the 75 moves rule?

First, there are positions where white can force a mate but with perfect defense by black it takes more than 75 moves to do (Ant referenced this reddit post) and that do not involve captures or pawn ...
• 255

### Does 'dead position' consider the 75 moves rule?

My feeling is that it should consider the 75 move rule. The current wording strictly speaking doesn't say that, as benediktwerner's answer explains (considering it only mentions "legal moves"...
• 28.1k
Accepted

### Questions about legality of last move

Answer to 1. For concise rules, FIDE differs between making a move and completing a move (and notating a move, which has no effects on play whatsoever, except that §8 is coming on you if you neglect ...
• 16.5k

Example showing why the checking condition is needed to make this an interesting puzzle: [FEN "k7/Pp4p1/1P6/8/8/6p1/1P4Pp/7K w KQkq - 0 1"] Whoever moves, the game soon ends in stalemate, ...
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Since Evergalo asked, I also post a solution, where neither side is in check at the start. Problem chess etiquette says that everything that the composer does not rule out explicitly isn't cheating - ...
• 16.5k

### A question about draw detection in chess engines

I actually did the experiment and will answer now. Three main factors go into the evaluation (as king safety doesn't play the slightest role): material, space, and movability. The effect of space is ...
• 16.5k

### A position in which there is no possible checkmate

I think that is limited to just a few positions. A lone king vs. king. king and bishop vs. king. A king and bishop vs. king and same colored bishop as the other side. A king and multiple bishops of ...
• 32.6k

### What happens if me and my opponent only have kings?

When you only have Kings then you can take a tour of the entire board till the end of the World without any hesitation . :-) (Just Joking ) . The Game at this point is a DRAW . Since neither Player ...
• 2,013

### What is sufficient mating material?

AFAIK sufficient mating material is considered as such if a "helpmate" can be demonstrated in any number of moves. Put another way, it is as if the player that ran out of time is out of the game, and ...
• 121

### When checkmate is impossible in a position

Update on the comment by usul. The algorithm is now described here: https://chasolver.org/FUN22-full.pdf It combines a search of variations with a dedicated mechanism for identifying blocked positions ...

### Has a position being a draw under FIDE 5.2.b before a forced recapture ever come up in a tournament?

Software which can answer this question now exists, but has not yet been applied to FIDE-rated tournaments. Miguel Ambrona (see https://chasolver.org/FUN22-full.pdf, presented at a conference in ...
• 12.1k

I think I have found a position meeting all the requirements, where White, on move, is not in check. Moreover, White can play a non-checking move. Legal position, 13 units, no promoted pieces. White: ...
• 16.1k
1 vote

### Open problems in chess involving maximum material imbalances

I think that these positions may be new, and push the boundaries of what has been done. They are better than anything I have seen. On the other hand, the notion of manual mathematical proof for chess ...
• 12.1k
1 vote

### What is "mating potential" in the FIDE Arbiter's Manual meant to mean?

It is perhaps worth starting by pointing out that the FIDE Arbiters Commission and the FIDE Rules Commission are two separate entities. This FIDE article defines what the roles and responsibilities of ...
• 98k

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