Greg Strong wrote on Sat, May 8, 2021 12:27 AM UTC:
Since you mentioned Ryugi in another thread (here) it reminded me that I wanted to mention it. There's a reason I hadn't implemented it in ChessV. Your pawn rule:
It can also move two squares forward on its first move
The difficulty is that you cannot always tell by looking at a position if a pawn on e3 or f3 has moved or not. (A pawn on d2, for example, could get to e3 by capturing.) So extra state information would need to be captured, and we'd need to define how the FEN notation is expanded to record that, etc. Since this game is so similar to Unicorn Great Chess, may I suggest using the rule from that game:
Any Pawn may make a double move from any space a Pawn of its color starts on
Since you mentioned Ryugi in another thread (here) it reminded me that I wanted to mention it. There's a reason I hadn't implemented it in ChessV. Your pawn rule:
The difficulty is that you cannot always tell by looking at a position if a pawn on e3 or f3 has moved or not. (A pawn on d2, for example, could get to e3 by capturing.) So extra state information would need to be captured, and we'd need to define how the FEN notation is expanded to record that, etc. Since this game is so similar to Unicorn Great Chess, may I suggest using the rule from that game:
This resolves the issue and simplifies the game.