Greg Strong wrote on Fri, Aug 27, 2021 12:23 AM UTC:Excellent ★★★★★
This is an interesting and logical approach to tackling how to have a double-move variant addresses pesky rules like check and en passant. They always require special-case rules to address, and how it is addressed here "feels" right to me. Marseillais Chess handles the check thing fine, but falls down on how en passant is handled. You seem to have neatly solved that, too. I also like how you are limited to one capture per move and cannot move the same piece twice. This also helps to preserve the strategical similarity to orthodox chess. I guess Marseillais is more of a "let's make double moves and we'll end up with an interesting but totally different game." Originally, it wasn't even "balanced" (white started with two moves.) This is an ambitious attempt to add the property of double moves games being "balanced" while changing as little else about the game as possible.
Extra Move Chess also provides similar benefits. You can make a second move, but don't have to, as long as it doesn't capture or move a piece that just moved. If you make a second move, it can be a two-space pawn move (which a first move can't, except for white's first move of the game.) This also neatly solves check and en passant.
I'd like to add this to ChessV. I think it's doable but I need to think some things through. The thing I see that most concerns me is this:
Each position created by a two move turn is included in the count toward a draw by threefold repetition, or toward a draw by the Fifty move rule (or the Seventy-five move rule)
If I understand this, it would be difficult to implement and doesn't make a lot of sense to me. Are you saying that any move in a single move turn or responsive move turn should not count towards the 50-move rule, nor should they be counted toward any potential repetition?
This is an interesting and logical approach to tackling how to have a double-move variant addresses pesky rules like check and en passant. They always require special-case rules to address, and how it is addressed here "feels" right to me. Marseillais Chess handles the check thing fine, but falls down on how en passant is handled. You seem to have neatly solved that, too. I also like how you are limited to one capture per move and cannot move the same piece twice. This also helps to preserve the strategical similarity to orthodox chess. I guess Marseillais is more of a "let's make double moves and we'll end up with an interesting but totally different game." Originally, it wasn't even "balanced" (white started with two moves.) This is an ambitious attempt to add the property of double moves games being "balanced" while changing as little else about the game as possible.
Extra Move Chess also provides similar benefits. You can make a second move, but don't have to, as long as it doesn't capture or move a piece that just moved. If you make a second move, it can be a two-space pawn move (which a first move can't, except for white's first move of the game.) This also neatly solves check and en passant.
I'd like to add this to ChessV. I think it's doable but I need to think some things through. The thing I see that most concerns me is this:
If I understand this, it would be difficult to implement and doesn't make a lot of sense to me. Are you saying that any move in a single move turn or responsive move turn should not count towards the 50-move rule, nor should they be counted toward any potential repetition?