Cut chess

This sound's like a reasonable variant. I think I have played something before where individual squares get removed (IIRC every starting square of a move - which makes the games rather short).

I don't think removing the outer lines could ever put you in check. This could only happen when removing inner lines.

@nadjarostowa said in #11:
> I don't think removing the outer lines could ever put you in check.
The only exception would be an automatic promotion of pawns which appear on the last rank after the cut. And the option suggested in comment #10 ("...will automatically become a queen or another piece of the player's choice..."), however natural, is quite problematic as then the opponent's decision of the piece to promote to would determine if the move was legal or not. (E.g. in the example from comment #4, if white decides to promote to a queen and rook, it makes black's Kf7 illegal, if white promotes to a bishop or knight, the move is legal.)

Indeed, I missed that - although you mentioned the auto promotion before.

One option is to leave them as pawns, and they can be promoted on the same square as a move without moving. But that adds quite a twist to promotions. Or you simply don't cut away the ranks if that would put a pawn on the last rank.

One could also think about adjusting the pawn's double step, or en passant. Or regaining castling rights after a cut.

But thinking of it more, it seems that board cutting will mostly effect the endgame anyway, with only very few cuts happening in the middlegame.

Here's a mate in one for you guys:

lichess.org/editor/7Q/8/8/k7/2K5/8/8/7N_w_-_-_0_1?color=white

@corvusmellori said in #6:
> How could this happen?

I found this a strange question coming from you of all people because it seemed to me that it is easy to construct a position for which removing a file or rank would give check from any piece other than a rook. But then I read nadjarostowa's contribution and realised that I had not understood the rules as given in the opening post. I see now that "If after any player’s move there is not a single piece left on the extreme vertical or horizontal line, then this vertical or horizontal line is excluded from the game." refers only to the edge of the board - I didn't see the significance of the word "extreme".

@nadjarostowa said in #14:
> Here's a mate in one for you guys:
>
> lichess.org/editor/7Q/8/8/k7/2K5/8/8/7N_w_-_-_0_1?color=white

Nice! Makes use of the fact that multiple ranks or files can be removed from the board with one move. (The rules in the opening post don't specify that, but it would make sense.)

@Brian-E said in #16:
>
I'm sorry. I don’t know English well and I can’t express my thoughts so accurately. This is exactly the idea. If it is possible to cut off several lines at once in one move, then this is allowed by the rules of the game.

@Andreyka7 I think your idea is a very good one for an interesting variant. The one problem I can foresee with it being implemented on a chess server such as Lichess is that the 8 X 8 board might be fundamental to the architecture and very difficult to vary. Maybe @corvusmellori might have some comment about that.

AFAIK the position of liches developers is that no more variants are going to be added; the reasons can be found in earlier discussions. IMHO one of the important problem is that many variants come with completely different concepts that would make designing a universal framework for all variants extremely difficult and possibly futile.

At first I did not see how reducing the board size could create a checkmate.

But now I see that it could. The checking piece, by vacating a rank or file, could cause the board size change, wich could then (by that size reduction) eliminate flight squares that otherwise would still have been available (despite the check) IF the board had not downsized.

It could also create a stalemate.

An 8 x 8 board could be reduced to 6 x 6, which would leave space remaining for 36 pieces -- so if this happened in the opening (very unlikely) it would still leave SOME room for all 32 pieces. In the middle game (still pretty unlikely) it would be even easier to accomodate.

In the endgame (where the size reduction would be most likely, it seems to me) the board size change MIGHT make for some interesting and faster endgames.

The more I think about the OP's idea, the more I think it is an interesting one. Nice, creative thought, @Andreyka7 ! Congratulations!