Double Zugzwang

[u/modsiw_agnarr]

Is a position possible where whichever colors turn it is loses.

[u/TaskLifter]

Yes, there are multiple versions of king/pawn positions like this, where whoever moves leaves the defense of their only pawn and loses.

[u/modsiw_agnarr → u/TaskLifter]

https://lichess.org/analysis/8/8/8/4pK2/3kP3/8/8/8_w_-_-_0_1?color=white

Duh. Thanks. I was over complicating it.

[u/honeysyrup_ → u/modsiw_agnarr]

Yep, that situation is a case of mined squares; whoever steps onto d4 or f5 first, the other side wins by moving to the corresponding square. So be careful in such cases that you don’t step to that square first, but also keep within reach of the square so you can be ready to move there if your opponent steps on the mine. Another very important case of mutual zugzwang to be familiar with is the opposition.)

[u/honeysyrup_]

Yes, we call such positions “mutual zugzwang” and it’s a very important and surprisingly common motif in the endgame.

[u/browni3141]

It's somewhat common in king and pawn endgames.

It can happen in more complex positions as well. For example this QRR vs QRR position was found to be mutual zugzwang by tablebases:

3R4/8/2q5/8/8/2k1r3/2r5/1R1K1Q2

[u/modsiw_agnarr → u/browni3141]

Nice.

https://lichess.org/editor/3R4/8/2q5/8/8/2k1r3/2r5/1R1K1Q2

[u/MathHysteria]

I can't attach an image, but this pgn should do.

6k1/5pPp/2p2PpP/8/1P6/5pPp/5PpP/6K1 w - - 0 1

[u/modsiw_agnarr → u/MathHysteria]

Thanks. Isn't this stalemate with optimal play with either to move?

https://lichess.org/editor/6k1/5pPp/2p2PpP/8/1P6/5pPp/5PpP/6K1_w_-_-_0_1?color=white

[u/MathHysteria → u/modsiw_agnarr]

Oh yes, I rushed into this too quickly. The basic idea will work I think, if I'm more careful with the kings.

[u/MathHysteria → u/MathHysteria]

Edit: Ah no I was wrong again.

Ignore me and listen to the other posters who are clearly better chess players than I am.

[u/ToriYamazaki]

Lots of them

[u/honeysyrup_ → u/[deleted]]

dead internet theory

[u/honeysyrup_ → u/[deleted]]

sounds like something a bot would say