H. G. Muller wrote on Mon, May 10, 2021 09:13 PM UTC:
It is not clear to me what happens when a Pawn is on 9th rank, and nothing of that color is captured yet. Is the move to 10th rank now forbidden? Or would the Pawn just stay a Pawn? (This could make sense to capture something.) If the move to 10th rank is forbidden, would it still check a King on 10th rank? Things would not be as complex if a Pawn was also allowed to promote to Fox (even though none was captured) on 10th rank.
It is not clear to me what happens when a Pawn is on 9th rank, and nothing of that color is captured yet. Is the move to 10th rank now forbidden? Or would the Pawn just stay a Pawn? (This could make sense to capture something.) If the move to 10th rank is forbidden, would it still check a King on 10th rank? Things would not be as complex if a Pawn was also allowed to promote to Fox (even though none was captured) on 10th rank.
Renniassance Chess