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The Quantum Chess Glossary

Every term the game and these guides use, defined once.

Written and maintained by Jasper Taylor for Pura Viba LLC · Updated July 30, 2026

Quantum Chess borrows a handful of words from physics and invents a few of its own. Here they all are in one place. For the ideas behind them, follow the links into the guides.

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Core concepts

Superposition: The state of a piece that is several possible identities at once. Every piece starts as a superposition of all six types. See Superposition & Collapse.
Possibility list: The set of identities a piece could still be. Reading a piece means reading its list, never its square.
Collapse: The narrowing of a piece’s possibility list as it is measured. A knight jump collapses a piece to a definite Knight; a quiet push barely collapses it at all.
Measurement: Any action that forces a piece to keep only identities consistent with what just happened. Moving is measuring; capturing is a hard measurement; a zap is a weak one.
Value ladder: The ordering of identities from cheapest to most valuable: Pawn < Knight < Bishop < Rook < Queen < King. It decides reach, capture value, and zap order. See The Six Identities.

Contact and its effects

Contact / touch: When a piece finishes a move, it touches every square it could capture on from its landing square. Contact drives both zaps and heals.
Cheapest self: A piece touches using its least valuable surviving identity. A fresh six-way blur touches only one square, like a pawn; you must collapse a piece to give it real reach.
Zap: A weak measurement on a touched enemy: it removes the most valuable possibility the target can cleanly lose, trying King first, then down the ladder. See Zap or Capture?
Heal: A weak entanglement on a touched friend: it restores the cheapest missing identity (King first if the side has no King possibility). See Heal Networks.
Capture: A hard measurement that removes a piece and collapses it to its least valuable possibility in the capture tray. Captures take from the bottom; zaps take from the top.
Volley: When one move zaps several enemies at once, the zaps resolve together as a single volley — they all shed or all shield.
Spillover / overflow: When a heal’s target identity is fully claimed elsewhere, the heal overflows upward to the next available identity. Late-game, this is how heals restore Queen or King.

The bookkeeping

Census: The rule that each side always owns exactly one chess set (8 Pawns, 2 Knights, 2 Bishops, 2 Rooks, 1 Queen, 1 King), across every consistent world. See The Census.
Conservation: The consequence of the census: identities can be revealed and moved but never created or destroyed on net. A background solver enforces it after every move.
Clean loss: A possibility a zap can remove without forcing a census cascade that rewrites other pieces. Only clean losses are allowed; the rest are skipped or fizzle.
Closed group: N pieces that together share exactly N identities. Every identity is load-bearing, so the group’s pieces shield until it is broken from the outside.

Shields and safeguards

Shield: The gold flash shown when a zap strips nothing — because the target is fully known, in a closed group, part of a failed volley, or protected by King Guard. See Shields.
King Guard / royal safeguard: The rule that a zap can never remove a side’s final King possibility. If a volley would strip King from every remaining holder, each keeps King and the zap falls through to Queen.
Royal spread: How many of a side’s pieces still hold King. Winning means driving the enemy’s royal spread down to one and revealing it. See Hunting the King.

Special moves and endings

Quantum castling: A once-per-game move on any two back-rank pieces that still might be Rook and King; they meet centrally and both become Rook-or-King. See Special Moves.
Promotion branch: Promotion applies only in the worlds where the piece was a Pawn; in other worlds nothing happens. A promoted piece wears a bar, never regains Pawn, and can snap back if the census later proves it was never a Pawn.
Checkmate: The only win condition. Once the enemy King is narrowed to one known piece, classical rules return and a revealed, trapped King is mated.
Kingless: A temporary state where a side has no King possibility. Play continues, and a later heal can restore King.
Mining: How daily puzzles are made: scanning real games for the moment one precise move mattered. See Reading the Daily Puzzle.

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