Ask HN: What do you think of this idea for a chess variant?

5 amichail 9 4/18/2025, 7:38:35 PM

This chess variant has one king and fifteen queens per side, and a piece may only move if it is adjacent to another piece of either color.

Comments (9)

Someone · 11d ago

Did you do anything to check this isn’t an easy win for either player?

I don’t see one, but do not rule out one, either. A series of sacrifices could lead to a position where white’s queens have a superior position over black’s ones, or vice versa.

mitchellpkt · 11d ago

I tried to find some way for white to force a win, but no obvious forcing sequences jumped out at me.

Like you said, "I don’t see one, but do not rule out one, either."

gus_massa · 11d ago

My guess is that it's possible to prove that each side can force a draw. Just exchange the queens until there are too few that you are back in a normal chess game.

I'm not sure if I'm underestimating the number of possible moves, that is huge, but I hope not sooooooooo huge.

mitchellpkt · 10d ago

Interesting. Hmmm, I have to think this through. I believe that if the game followed normal chess rules, except for replacing the pieces with queens, then games where the captures are all even trades would result in draws, but if one side could come out ahead with K+Q vs K, then there would be the usual mate sequence.

HOWEVER the rule OP added that "a piece may only move if it is adjacent to another piece of either color" slightly complicates the endgame. My normal tendency would be to put the queen far away from the action to avoid blundering it, but here that would instantly deactivate it. It's kind of funny to picture the kings racing across the board to capture or reactivate the last inert queen.

I think one can still get the usual style of mate in this variant, you just have to walk the king and queen together, and pay extra attention to avoiding stalemate. For example, imagining white king on e1, black king on e3, black queen on d3. If white to move then Qb1# or Qe2#, fairly standard maneuvers (though if black to move that's a stalemate).

This is an interesting modification to the game, I'd play a few rounds...

Someone · 10d ago

> It's kind of funny to picture the kings racing across the board to capture or reactivate the last inert queen.

That would never happen. Because of the “of either color” clause, a king can’t even move to a square adjacent to a queen of the other color, as that activates the queen, moving the king into check.

Also, if the kings are included in the “piece” category of “a piece may only move if it is adjacent to another piece of either color” (which, I think/guess the OP didn’t consider), a lone king cannot race across the board.

mitchellpkt · 9d ago

Oh yeah totally agree, I was thinking of the king as separate from the pieces. If a lone king cannot move, that changes the dynamics considerably.

AnimalMuppet · 10d ago

I could see an endgame where the last exchange leaves all the remaining pieces isolated from each other. By the rules, then, no piece on either side can move. Stalemate? Or a flaw in the rules?

Someone · 9d ago

My guess/intuition is that the first player to move can win. I see two strategies that may work:

- use your queens ‘from the outside in’ to give check, forcing your opponent to take the queen giving check. In the long run, isolate an enemy queen in a corner, effectively removing it from play and giving you a surplus queen. Then, keep exchanging queens.

- use your queens to give check, forcing the queens near the enemy king to take them. Once the enemy king is isolated, it cannot move anymore, so giving check becomes dangerous. Black will have to either take the queen giving check or move a queen into the line of sight.

muzani · 11d ago

Ah, the anime variant.