Questions tagged [illegal-move]

A move that doesn't respect the rules of chess.

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4
votes
1answer
66 views

How can I use pgn-extract to remove a game from a pgn file when there is an illegal move?

How can I use pgn-extract to remove a game from a pgn file when there is an illegal move?
30
votes
3answers
12k views

Can a piece pinned to my king put the opponent's king in check?

I was playing a game with a friend online. A situation came up where he put me in check with his bishop, and I moved my rook to block it. His king was on the g file and my rook was on g2. The website ...
21
votes
5answers
27k views

Why is castling through and out of check prohibited?

Why is castling disallowed when the king is in check or when the square the rook will be placed on is under attack? What is the rationale behind this ruling?
5
votes
3answers
2k views

Can a king be checked with another king when checking square is protected by the side which gives the check?

Can a white King move next to a black King to check it, if there is a white pawn protecting the white King, preventing the black King from taking the white King?
2
votes
3answers
288 views

How to notify check when a player leaves himself in check

I'm learning to play chess. Twice we had a situation where the white player moved a piece that was blocking the black Queen from checking the white King. There was no move available to announce "...
6
votes
1answer
318 views

Can a win be claimed on the second illegal move if the first wasn't raised?

First of all, I don't think this is a duplicate of what happens on the first illegal move in a game. This is what happens after the second if the first is unclaimed. The setting is a tournament under ...
-4
votes
2answers
167 views

Is it possible to make an illegal move legal? By anyway? [closed]

I somehow make an illegal move, any kind. Can I then make it legal? If so, how? What are all the ways an illegal move can be legal? Is it possible to make any illegal move legal?
1
vote
2answers
139 views

In a tournament game, what should a player do if he find that his opponent's position is impossible, which was caused by an earlier illegal move? [duplicate]

For example, if a player realises that his opponent has two bishops of the same colour after a certain legal move (and assuming that it is clearly not caused by any pawn promotion), which implies that ...
0
votes
4answers
229 views

Blitz Touch Move Rule

In a "friendly" blitz game I got into an argument with my opponent in the following scenario: My opponent's knight was pinned to his king. He did not notice and touched his knight to move it. I ...
2
votes
1answer
182 views

What happens if a player makes an illegal move and nobody notices?

What happens if a player makes an illegal move (i.e. a realistic case could be, he castles after he already moved the King), but none of the player notices, and the game goes on and on for a lot of ...
5
votes
1answer
404 views

Can you claim an illegal move in Blitz after pressing your clock (but without making a move)?

In Blitz under FIDE rules, Player A makes and completes an illegal move by pressing the clock. Player B states that Player A's move is illegal, does not make a move, but quickly presses his own clock, ...
1
vote
3answers
190 views

What happens if I push a pawn to the 8th rank and press the clock before promoting? [duplicate]

What happens if I push a pawn to the 8th rank and press the clock before converting it to another piece? Does it make a difference if it's Blitz or not?
-2
votes
1answer
85 views

Checking on the legality of a move [duplicate]

I moved my white King to d4, taking black's bishop. This put the king in a checkmate with black's knight on c6. Is this move legal or illegal? Thank you.
4
votes
3answers
13k views

Moving king into check

Can a player move their king into check if the opponents piece that is able to take king, is putting opponents king in check?
4
votes
2answers
314 views

can I move a piece protecting the king if it keeps protecting on its new location?

Situation: there's a piece between the king and an opponent piece. If this piece were not there, it would be a check. If I were to try and move the protecting piece somewhere and leave the king ...
9
votes
2answers
816 views

Touch a piece and then claim opponent's previous move was illegal

In a last round tie between 2 players fighting for top seed in a competition, here is what happened. White had 18 seconds on his clock and black had 26 seconds. Black was winning. At move 56, black ...
1
vote
2answers
100 views

Way to Logically Predict Approximate Chess Rating in Pop-Culture Games [closed]

After seeing a video of an analysis on the chess game in A Game of Shadows between Sherlock Holmes and Moriarty, it made me wonder what their fictional ratings would be around. Other games like the ...
17
votes
5answers
3k views

Are there any illegal positions that are difficult to spot?

I have a question and I'm sorry if it sounds very uninformed, I'm not a professional chess player so my interest is mere curiosity. I was wondering if there are examples of illegal positions that ...
2
votes
1answer
217 views

Are there any legal positions known to be impossible to come to in a normal game? [duplicate]

There are some fairly obvious ways to set up a chess board that cannot possibly happen: both kings simultaneously in check would be one. There are some positions that seem impossible in a normal ...
6
votes
1answer
398 views

Illegal Move Missed — Too Late?

Standard game, USCF rules (if FIDE is different, I'd like to know). One side makes an illegal move -- specifically, castling through check. Neither player notices. Five moves later, the same side ...
27
votes
2answers
21k views

I made an illegal move. What happens?

Especially in blitz or bullet games, it is possible that a player makes an illegal move, for example castles through check. If the opponent does notice the illegal move, then as far as I know the ...
0
votes
1answer
226 views

Rook and knight used together within the same move - legal?

This is my first question on chess beta and I don't know if I'm insane or if the cpu is broken. So I was playing chess against a CPU on the iPhone with the app 3D Chess Game, and the CPU (playing ...
5
votes
2answers
865 views

Detect pinned pieces code

This post is a follow up of this one: C++ vs Java Engine move generation performance My goal here is to improve the performance of my move generator, which finishes perft (start_pos, 6) in 8.5 secs. ...
12
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5answers
4k views

How to know when a FEN position is legal?

I am doing a personal project, where at one point I need to validate the FEN position, I started with some basics checks, such as check if there are kings and making sure there aren't any extra rows ...
6
votes
2answers
345 views

How to create PGN notation with wrong moves in it?

I was as chess trainer with some young guys on a tournament, and wrote down some of their games. In nearly every game, there were wrong moves in it: king is in check, but does not move or react; ...
4
votes
2answers
168 views

Is this move valid in the rollerball chess variant?

Can the white King move a space to the right, into the original location of the black king? This would be disallowed in standard chess, as one cannot intentionally put themselves into check. However, ...
0
votes
4answers
375 views

Is it possible to play 1 minute bullet with no increment over the board?

Playing 1 minute bullet with no increment on the internet is already hard... but what about over the board? i.e. in real life with an actual wooden board. Would it be possible or would 90% of the ...
8
votes
2answers
936 views

What “double moves” are sometimes considered legal?

As we know, castling is a legal "double move," where two pieces are moved at once. But in my country, Indonesia, in my childhood, the opening below was an 'assumed legal' double move to counter 1.e4 ...
1
vote
2answers
217 views

Illegal move or forfeit on time - who wins this 5-minute match?

In a 5-minute match a player makes an illegal move leaving his king in a check position. This usually gives the victory to the opponent, if he sees it and captures the king. Otherwise, if the opponent ...
5
votes
1answer
212 views

Why isn't the active color allowed to be in check in a FEN legal position?

The title says it. Reading up on how to describe the position of a board, all of the requirements make sense (like two kings not being on adjacent squares and so on) except for the active color being ...