What the site does
Mahjong Lore does the counting that slows a game down. The riichi score calculator finds the yaku, han, fu and payments of a winning hand; the fu calculator explains fu line by line and prints a points table; the shanten calculator shows how far a hand is from tenpai and what to discard; the Hong Kong faan calculator counts faan and turns them into points; the tile guide names every tile and checks a set; and how to play walks a beginner through a first game.
How it works
Every calculation runs in your browser. Nothing you tap or type is sent anywhere, and the tools keep working if you go offline after the page has loaded. The site uses Cloudflare Web Analytics, which counts page views without cookies or cross-site tracking and never receives what you enter into the tools. See the privacy page for details.
Which rules
Riichi scoring follows the European Mahjong Association's Riichi Rules for Japanese Mahjong, 2025 edition, with the WRC Rules 2025 as an option and common house rules as switches. Hong Kong scoring follows the Hong Kong Mahjong Association's rulebook, with an editable points table because home games vary so much. Tile counts and set contents come from those rulebooks, the Chinese Official Mahjong Competition Rules (2006) and, for American sets, the National Mah Jongg League's own description of the game. Each page lists its sources and the date they were checked. Mahjong Lore is not connected with any of these organisations, and it does not reproduce the National Mah Jongg League's copyrighted card.
Shanten and tile counts are mathematics rather than rules: they are worked out exactly and checked against an independent brute-force search in the site's tests.
Fonts and tile drawings
Headings are set in Hahmlet and text in Ubuntu Sans, both under the SIL Open Font License and served from this site. The tiles are drawn for this site; the Chinese characters on them are outlines taken from LXGW WenKai TC (Copyright 2024 The LXGW WenKai Project Authors, SIL Open Font License 1.1), turned into drawings so that no Chinese web font has to load.
Scores are calculated from the rules as published; when your table plays differently, your table's rules win. Mahjong Lore gives no gambling, legal or financial advice.