7

I am looking for positions from where every move is forced up to a certain depth. If the original position (or one in between) occurs again, the sequence is finished there.

3
  • Do you mean that every move of both players is forced or of just one player? (In the first case, mates in N moves are out of the question, because the moves of the losing side are not forced as his decision makes no difference.) – JiK Apr 3 '14 at 13:41
  • Yes, it's about forced sequences for both players. It doesn't need to end in checkmate, the only requirement is that there is just one possible move for each player for a long time. – chaosflaws Apr 3 '14 at 16:00
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    I think it eas not intended by the one asking the other question but it is trivial to construct a position that is forced to repeat again and again, making that sequence infinite. – chaosflaws Apr 3 '14 at 20:49
4

9 moves

In the linked thread (not quite a duplicate), a valid answer is posed to this question:

You mean like this?

[Title "Vilhelm Röpke, Skakbladet 1942, Mate In 6"]
[FEN "K1k5/P1Pp4/1p1P4/8/p7/P2P4/8/8 w - - 0 1"]

White mates in 6.

I guess that's 9 consecutive forced moves. It would be eleven except for black's choice of promotion piece on his fifth move. I don't know if it's a record, and I don't know who composed this classic chess problem.

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  • I miss understood what the OP was asking, I end up deleting my answer and upvoting yours since it goes straight to the point. – dreamcrash May 21 '14 at 13:43
  • Can c1=Q be considered forced? I mean surely I had C1=N, C1=B, C1=R – Alan May 21 '14 at 18:32
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    @Alan It's not counted in the 9 half-moves for that reason. ("It would be eleven except for black's choice of promotion..."). – Daniel Jun 12 '14 at 10:32

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