Chess engine

Fairy-Stockfish WASM via npm (direct packageSource). No database or catalog — local ui showcase only.

Play vs Fairy-Stockfish and inspect MultiPV analysis. Engine package loads from npm — no DB or catalog.

Idle

Play vs engine

Toggle which side(s) the engine plays, then Start. The engine moves automatically when it is that side’s turn.

To move: —

#1 is the engine’s best line for the side to move.#2 and #3 are the next-best alternatives (MultiPV).

Scores are in pawns from the side to move’s point of view (not “was the last move good?”).
+1.42 ≈ that side is ahead by about a pawn and a half;−1.42 ≈ they are behind by that much. 0.00 is equal.
M3 / −M2 means mate in 3 for the side to move, or mate against them in 2.
While searching, lines fill in unevenly (e.g. #1 still “—” while #2 already has a PV). Wait for depth to settle, or press Stop. A dim best-move arrow on the board tracks #1 as depth improves.
Use EN / 繁 / 简 to show moves in locale notation. Click a line to open it on a board with a full move list.

Auto-analyze on move

Analysis Analysis

— Depth —

— — 1 thr

Needs cross-origin isolation (COOP/COEP). Open this page via ui:dev orui:preview.