Play › Guides › Hunting the King
You don’t find the King by looking. You find it by deleting it everywhere else.
There is no victory by wave-function collapse in Quantum Chess. The quantum midgame is checkless, because a maybe-King is a possibility, not a target — you can’t check something that isn’t definitely there. Winning means dragging the game back to classical chess for one specific piece: narrowing the enemy King down to a single revealed piece and then mating it by the old rules. The endgame, therefore, is less a battle than a counting exercise. Here is how to run the count.
The single number that matters late is how many enemy pieces still hold King on their possibility list — the royal spread. A wide spread means the classical endgame is far off; a narrow one means concrete checkmate calculations are finally possible. Get in the habit of counting the enemy’s King-holders every few moves. Your whole plan is to drive that number toward one.
You reduce the royal spread with the same tools you’ve used all game, aimed at a new goal:
When the enemy King narrows to one known piece, the classical rules snap back on for it: it may not be left en prise, a check is a real check, and a revealed King with no legal escape is checkmate. Everything you know about classical mating — cutting off escape squares, using two pieces to build a net, driving the king to the edge — applies again, but now against a single revealed target while the rest of the board is still quantum. Line up the reveal and the mating net together so the King is cornered the instant it’s exposed.
A subtlety that saves — and wins — games: if some resolution temporarily leaves a side with no King possibility, play continues. That side isn’t checkmated; it’s momentarily without a royal identity, and a later Heal can restore King to a friendly piece (Heal tries King first when the royal identity is missing). So don’t assume the game is over the instant the count hits zero on either side — and if it’s your King that vanished, look for a heal to bring it back before your opponent forces a real mate.
Defense in the endgame is the mirror image: keep your King diffuse. Avoid voluntary King sheds — recall that a knight jump from a King-holding piece drops King unless it’s your last royal holder. Use heals to keep several of your pieces royal-capable, forcing your opponent to do far more counting work before they can ever line up a reveal-and-mate. The player whose King reveals last usually wins.
Endgames are where advantages drift into draws. The fifty-move rule counts progress as any net loss of possibilities, so heal-shuffling in a static position makes no progress and walks toward a split point. If you’re winning, keep the count moving — every few moves should strip a real possibility from the enemy, not just re-blur your own army. Reveal, corner, mate, and keep the clock working for you.