TITLE: How many consecutive forced moves are possible in chess?
QUESTION [5 upvotes]: The question concerns chess. I call a move forced if, in a given position, is the unique move consistent with the rules of the game. I wonder what is the largest integer $n$ such that there exists a legal position in which:

both black and white have forced moves for $n$ consecutive times;

the position is never repeated (with the same color having to move).


Notice that without condition 2., the answer is $\infty$.

REPLY [10 votes]: This question has been answered at chess.stackexchange.com. It seems that if you allow promoted pieces, the current record is $n=9$.