The Bug Thread

Thanks, I didn't think about it. I went outside the walls of the 4pc world and took a walk. Thinking with a fresh mind, I signed the coordinates on the screen with a flamaster

да, фломастер - важная вещь...

https://www.chess.com/4-player-chess?g=4565675

Bug with points + game end

That bug was there a long time ago applied on "hailstorm" the variant, when a game end,it just counts all the point value of pieces that belong to zombies.

so this could happen:https://www.chess.com/4-player-chess?g=4565751

well, idk how this happened, but I clicked something and the times/language got all screwed up. And if you know these players, these are NOT their ratings, and the profile pictures are on the wrong usernames. Jeeeez i messed this up badly.

Chess.com freezes when i setup a bot match between other players. Ill set a color for one player and when i try to change that players color chess.com freezes but i can workaround this if i set a different player with the color that the other players color is set to.

In Team mode a player is unable to capture an opponent king when in check.

Bug or not?

In the linked game:  18. yRf6+ gQxf1+ and red cant take blues king even though he is in no danger after the illegal 19. rBxb7 yRxf1

Red should be able to ignore the check and take blues king.

https://www.chess.com/4-player-chess?g=4637492-71

Correct me if I'm misunderstanding, but you're looking at:

18. Rd1-f1 .. Ra11xBa9 .. Rc6xb6+ .. Qxf1+
19. Bg2xKb7#

For standard play, the ruleset is identical to 2-player chess, except where adjustments have been made for the 4-player modality. As in 2-player, if a player is in check, on his turn, he must protect the king with ultimate priority. Even though in this instance it means that he's prevented from winning the game, the rule is applied regardless. A move like Qxf1+ is a good resource for Blue/Green here, in fact the only continuation resource.

You are able to change this condition by applying the "Regicide" gamerule, in which players are not beholden to protect their king with ultimate priority, and checks/checkmates are entirely superfluous. As a consequence of that gamerule, you can perform king captures, even if your king is under threat.

@grable, after Rc6-f6 red is in no danger because yellow just recaptures the queen before green could take the king.

One could even argue that they respond to the check as they have 2 moves to do it, reds and yellows turn. So the rule of checks having ultimate priority is not even violated if you count ry as one team.

I have long suggested to change these rules but kept meeting resistance. for example: https://www.chess.com/clubs/forum/view/survey-teams-king-capture-rules.

That said i took another attempt recently and all admins seem ok with it too now, so I'll use this bug report to justify the change that will go out potentially as soon as tomorrow

It is all a question of prioritization. With current standard rules checks and checkmates have higher prioritization than king captures. A player in check has to make a move to escape the check on his own turn, just like in 2 player chess, if he cannot he is mated. It doesn't matter if enemy kings are hanging or if the teammate can interfere in time.

However, it seems now that there will be a slight change in the rules coming soon so that capturing an enemy king in Teams counts as stepping out of check/checkmate. 

An interesting alternative is the Capture the king/Regicide rule that @grable mentioned. There the following line from https://www.chess.com/4-player-chess?g=4637492-71 would even work: 17.y Rxc4! leaving yellow's king in threat from blue, but as 18.r Bxb7 is unstoppable the yellow king is safe. 

fwiw we changed the exact same thing for FFA 6 months ago, and did not do the same for teams because of the ongoing W4PCC. So this is overdue

I read some opinions in the forum and thought about it, i think i like it the way it is now even though it's not quite logical. It makes up for some cool tactics, like checkmates that ohterwise wouldnt be possible and also you don't have to worry about hanging your king to check.

The "Capture the King" variant is somewhat flawed though. You can castle through checks. Instead there should be some kind of en passant rule where you can take the king and even your teammate being able to block the en passant king capture. But no one plays that mode so... who cares.

because if we didn't put players in the highest rated games, the high rated games would never fill up.

to avoid it, look at the PLAY tab and choose a game from there. Or click custom and set a rating range with an upper limit.

yes. sorry i wasn't thinking teams invites, because there what happens is only when the challenge is accepted, does it look for a suitable game. (the game you invited to may long be gone or filled up).

better, click custom and set a range (and invite from there)

because it searches for a matching Q on accept, regardless of the actual Q used for the invite.
you solve this easily as shown above so the Q that is used to match against has a rating range.
on accept, if the range conflicts with 1800+ it will pick another Q for you. (and if none found, start a new one)

Hi, I ended up second instead of first in this game, because of a bug: https://www.chess.com/4-player-chess?g=4996833

On move 74, green loses on time, and then there are just three kings remaining, without pieces. At that moment, the game should had automatically ended, and red and I should had earned ten points each.

That didn't happen. The game didn't end automatically, and it was my turn, but the system didn't allow me to made any move. So, I lost on time, red got 30 points, and I only 10.

In this game i lost on time, when i should have been checkmated (it should be a double checkmate) https://www.chess.com/4-player-chess?g=4793433-256
That made all players have to unnecesary wait

important rules Bug

https://www.chess.com/clubs/forum/view/coding-error-for-double-checkmate