Villager Chess

Ever wondered if that Master-level librarian is actually smart? Challenge them to chess and find out.

Open any villager's trade screen and hit Play Chess. A full chess board opens right there - no items, no commands, no setup. You always play White.

How strong are they?

A villager's trading level sets its chess strength:

Villager level	Chess strength
Novice	Hangs pieces, misses mates
Apprentice	Punishes only blatant blunders
Journeyman	Solid club beginner
Expert	Strong; rarely errs
Master	Near-unbeatable

So a fresh Novice is a free win - but if you want a real fight, trade one up to Master first.

How to play

Click a piece, then click one of its highlighted squares.
Pawns reaching the last rank open a promotion picker.
Full rules are enforced: castling, en passant, threefold repetition, the 50-move rule, and insufficient-material draws.
Resign with the button, or just close the board. Walking more than 16 blocks away, the villager dying, or disconnecting abandons the game.
No stakes, no rewards - just for fun (and bragging rights).

Under the hood

A from-scratch pure-Java chess engine: 0x88 board, full move legality, Zobrist hashing - move generation verified against perft reference counts.
Negamax search with alpha-beta pruning, iterative deepening, and quiescence, on a background thread so the server never stutters.
Fully server-authoritative: the server owns all game state; clients only send move attempts.

Compatibility

Plays nicely with the other Villager Games mods - the trade-screen buttons stack instead of overlapping. Requires Fabric API.

Requirements

Minecraft 26.2
Fabric Loader 0.19.3+ and Fabric API
Java 25
Install on both client and server (works in singleplayer out of the box)