Open standards for mahjong
A home for open, freely implementable standards for the game of mahjong — so tools, apps, and players can share the same data without lock-in.
First standard: the Mahjong Portable Format (MJPF). A compact, deterministic way to share a mahjong deal, challenge, or replay as a short code or a QR — no server, no account.
The Mahjong Portable Format
Because a mahjong deal can be reproduced deterministically, an entire hand — the wall, the deal, and the move-by-move ledger — fits in a QR code. MJPF specifies exactly how, so any app can read and write it and reproduce the same game byte-for-byte.
Deals & challenges
Share a starting deal or a beat-my-score challenge; the recipient plays the identical tiles.
Replays
Share a whole game as a view-only replay — the recipient presses play and watches it unfold.
Open & published
A public specification with a JSON schema, example payloads, and an implementer’s guide. Free to implement.
Reference implementation
MJPF is implemented in Mahjong Master Coach, a single-player mahjong game and coach for iPhone and iPad — its share and import features round-trip through the format.