About This Site

Three Ways to Play

• Against AI: Choose Cho or Han, pick from multiple locally computed levels, and compare ideas with hints, undo, and move-by-move replay.
• Two players: Share one device for face-to-face play, teaching the rules, or discussing alternatives from the same position.
• Online rooms: Open a public or private room, choose a side, and invite an opponent by link or room code. Public rooms may also be joined or watched from the lobby.

See Janggi Rules for the rules and Janggi Tips for practice advice.

Local Games and Online Rooms

AI and same-device games stay in the current browser. This includes the position, move record, and a few interface settings. A refresh will usually preserve the game, but clearing site data removes that local progress.

Online play is different: the server temporarily holds room state and synchronizes moves, while the browser keeps the identifiers needed to reclaim a seat. Those identifiers are not a user account. The Privacy Policy explains the data involved and how it is removed.

What the Site Does Not Provide

• No player ranks, rating tables, social accounts, or skill-based matchmaking.
• The public lobby lists open rooms, but it does not pair players automatically.
• AI moves, live analysis, and hints at every level come from Fairy-Stockfish running locally. They are not professional coaching or an official rating.
• Normal play does not ask for an email address, phone number, legal name, or payment details.

This site implements Janggi, Korean chess, on a 9×10 board. It is not xiangqi, shogi, or Western chess, and there is no river. If the written rules and the legal moves accepted by the board disagree, the program or documentation should be corrected; the discrepancy is not an alternate ruleset.

Why Each Feature Is Here

Every feature should help someone complete a game or understand a move. Board cues identify legal destinations, the move record makes it possible to revisit a decision, and room status confirms seats and connections. Accurate rules, clear feedback, and consistent legal moves across all modes matter more than adding another menu.

Where the pieces come from

The octagonal pieces and the 9×10 board are drawn by this site, not taken from a third-party piece set.

The engine behind the AI

When you play the AI, every level’s moves and live analysis come from the open-source Fairy-Stockfish engine with the public Janggi neural network file janggi.nnue (about 11 MB, from the janggi-9991472750de lineage). It searches inside your browser, so your game is not sent to anyone else’s server. Lower levels cut strength with a lower Skill Level and a depth cap; Master searches at full strength for the think time you choose. The panel shows that same search: depth, node count, speed, evaluation, and the main line.

Fairy-Stockfish is led by Fabian Fichter (ianfab) and grew out of Stockfish. The fairy-stockfish.wasm build is what lets it run on a web page. The engine is licensed under GNU GPL v3; the full license is in COPYING and the author list is in AUTHORS. Our thanks to everyone who turned search and evaluation into free software others can build on. None of these authors endorse this site.

If the neural network fails to load, play continues on the classic search engine and the panel no longer shows the same search details. Legal moves, game end, and bikjang are still decided by this site’s own rules code.

About Ply Yard

This site is maintained by Ply Yard. We investigate reports against this board, its rules, and its room service. If the board accepts an illegal move, rejects a legal one, loses sync with the move record, or fails to reconnect a room, please contact us with reproducible steps.