You complete Usowan when the shading satisfies the base adjacency rules and every room contains exactly one clue whose count is correct. The engine evaluates the full position rather than relying on a visual shortcut or an unsupported solvability claim.
Your unfinished game is saved only in this browser.
You complete Usowan when the shading satisfies the base adjacency rules and every room contains exactly one clue whose count is correct. The engine evaluates the full position rather than relying on a visual shortcut or an unsupported solvability claim.
Complete guide
Usowan uses the independently implemented Nikoli Usowan rules v1 profile (R470). Usowan is a complete deterministic browser game whose distinct rules centre on room clues of which exactly one is truthful while all other numerical claims in the same room must be false.
Usowan opens from a versioned seeded position built for room clues of which exactly one is truthful while all other numerical claims in the same room must be false. Its game ID, rules profile, and deal identity are stored together so restart recreates the same opening without a server request.
Every Usowan action is checked against the current board, available material, and this defining restriction: a room with zero or multiple truthful clues is invalid even if all shaded-cell connections otherwise look complete. Invalid, stale, or post-terminal actions leave the position unchanged.
You complete Usowan when the shading satisfies the base adjacency rules and every room contains exactly one clue whose count is correct. The engine evaluates the full position rather than relying on a visual shortcut or an unsupported solvability claim. Near the end of Usowan, recount the remaining obligations needed until the shading satisfies the base adjacency rules and every room contains exactly one clue whose count is correct. Check the boundary rule after every final placement or transfer because terminal status is enforced immediately.
A practical Usowan plan is to preserve several legal continuations around room clues of which exactly one is truthful while all other numerical claims in the same room must be false. Use the deterministic hint to inspect one legal action, then compare how it affects the documented objective before committing. A common Usowan error is to ignore the boundary rule that a room with zero or multiple truthful clues is invalid even if all shaded-cell connections otherwise look complete. Undo is useful for studying that decision, while restart deliberately preserves the original seeded position.
Usowan has its own runtime and save identity because its rules require room clues of which exactly one is truthful while all other numerical claims in the same room must be false.
a room with zero or multiple truthful clues is invalid even if all shaded-cell connections otherwise look complete.
Usowan stores its game ID, rules version, and seeded deal identity. Those values recreate the same opening locally without promising that the position is forced or winnable.