makes a lot of sense. but will it be more fun than what we have now? i love all the funky mates and the challenge not to give them to your opponents.
concerning stalemate, when there are only 2 players left standard chess rules would make sense (the stalemate-bug topic).
i think 4pc checks for check- and stalemate for all 4 players on each move. it doesn't matter if it might no longer be mate (or stalemate) on the mated players turn. you might expect this for stalemate, but for mate?
here's a game i observed. how would changing the rules affect play i wonder?
red took greens h3 pawn thanks to a pin. blue then checked on g2 using the red bishop as cover. Kh1 by green. red's discovered check isn't mate as green could now take the rook. (blunder by red!) blue then mates by pulling back the rook (green cant block)
I propose a solution of the "Checkmate in 4 Player Chess" problem.
(This is a separate topic is to focus on the checkmates only. Some ideas were discussed here:
https://www.chess.com/clubs/forum/view/new-checkmate-dead-king-rule )
The solution is to consider the checkmate as the end of the game for the checkmated player, but give +20 points to the player which actually captures the king.
An example:
1. Red checks the green king. No points awarded (if it is not a check to 2 or 3 kings at the same time).
2. Blue attacks the square(s) of the escape path and/or checks the green king, so we have a case when 1) the green king is under a check (by red or by both red and blue), 2) green king does not have an escape path, 3) green player can not remove both the threats by a single move.
3. Yellow makes some move that does not change the green's situation.
4. At this moment (at the beginning of green's move) this is considered as a checkmate. As a result the green leaves the game, all his pieces except his king become gray. The king stays on the board and can be captured.
5. Red (or blue, or unlikely yellow) capture the green king and get +20 points.
This way we keep the chess spirit in this game and also resolve the problem "who should get those +20?"
Some modifications are possible, of course. For example, we can give some bonus (+10?) to the blue at step 4. And currently step 3 does not work (the server does not wait for the yellow's move, that is strange in my opinion).