Questions tagged [illegal-move]

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

Filter by
Sorted by
Tagged with
5
votes
1answer
268 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 ...
21
votes
7answers
6k views

How do you know when a FEN position is legal?

I am making a research on validating FEN positions, at first it is obvious the basics things to look for, such as checking if there are only two kings and making sure the rows or columns add up and ...
34
votes
2answers
25k views

Is taking the opponent's king an illegal move?

In competition blitz games, making an illegal move and then pressing the clock forfeits the game if the opponent claims the illegal move as long as they do not make a new move, as a new move would ...
38
votes
2answers
40k 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 ...

1
2