Tenhou Documentation


Here's documentation on the popular online mahjong client 'Tenhou' (天鳳). What with the entire website and client being in Japanese, English documentation would be pretty useful to novices. Though this doesn't teach mahjong in itself, it should explain Tenhou inside out for the end user. Email for typos, dead links, errors, complaints and such.

If you are interested in how Tenhou works, you probably want my Tenhou Protocol Documentation, which echoes some of the content here from a more technical viewpoint (for anybody interested in implementing a version of Tenhou themselves, the documentation is real helpful). There are also some tools and such to have a look at.

This documentation is split up into various files for different topics. That's basically to make it more straightforward to navigate and write. Initial dates of writing are at the top of pages, while the most recent modification dates are at the bottom.

Lots of stuff in this was translated or explained to me by people on #mahjong/Rizon. Blame them for this too. Direct contributions noted also.

This doesn't cover how to play riichi mahjong, only how to use the online client Tenhou. See Other Resources for a list of tutorials and links relative to learning.

I'm always working on this, while it might not be so apparent. See the ChangeLog for all edits done, and TODO for stuff that I plan on doing. Please also note that this documentation and resources are all under an Attribution-Noncommercial-Share Alike license.

2014-01-09 — Japanese mahjong wiki announcement
Thanks to the great work of the guys from IRC, there is now a growing wealth of information contained in the Japanese mahjong wiki. Feel free to join the effort!

records/statistics database | blog | protocol documentation | wiki


Lobbies and Games
User IDs and Ranks (Rate)
Watching Games
Purchasing an ID
Frequently Asked Questions
Network Protocol Documents and Resources
Glossary (including yaku, game modes, ranks and rounds, among other things)


Game records/statistics database
Tenhou Protocol Documentation and resources
Japanese mahjong wiki
ロンDB (ron DB) riichi hand screenshot database
Memberlists, generated automatically
Hand Score Quiz and Yaku Quiz Java applets by UmaiKeiki
Mahjong message board for tournament registrations, discussion and whatnot
Tournament results in plaintext form
Game records, updated every 30 minutes
Houou game logs, updated twice daily
Wait Calculator notes (very rough notes)


Blog I run on technical mahjong related things (old)
Tenhou main page
L7447 Tenhou English lobby
Osamu's mahjong blog
"So you want to play Mahjong" Riichi Tutorial - friendly riichi guide, .doc form, teaches Ari Riichi
Modern Japanese Rules - terminology, expanations and hands/scoring on riichi
Toudai-shiki Mahjong Scoring - very comprehensive Mahjong scoring page, has lots of terminology too


  • 2012-10-28 - More changes, specifically updates to championship details and the FAQ.
  • 2012-10-25 - This time I actually updated stuff. Check the ChangeLog! I'm also holding a design competition. I expect no entries.
  • 2011-11-11 - It's been over two years since I last added a news entry. I have used the blog to report both major and minor events, for better or worse. This website has been neglected (although not forgotten!) for a while, and I have promised multiple times to update quite a few things. A migration of arcturus.su to a new server will prompt a reworking of a lot of the flaws in the site's backend code (manifold they are) - which is good for me! - and a rebuilding (hopefully!) of the ranking.pl database, meaning a patch of any data deficit/surplus - which is good for you! In the process I hope to bring these pages up to date, as a lot has changed in these years. I have plans to make the protocol documentation public as well.
  • 2009-09-27 - Added a page on Tenhou's championship mode. This is long overdue, but probably still worth adding.
  • 2009-07-28 - The game records/statistics service is complete (it has been for some time) and now properly uses a MySQL backend and all (here are some fancy graphs and figures). I haven't added NEWS in forever because scratch has been a much more lazy method as of late. On that basis I suggest checking the centre of the page more often.
  • 2009-04-13 - Added a 7447 statistics/games lookup thing.
  • 2009-04-07 - Added a screenshot guide to purchasing an ID for Tenhou. You'll also have noticed that /prot/ is forbidden; that's because C-EGG asked me to not have it public. If you really want it, email me.
Older news


#mahjong@irc.rizon.net - Mahjong IRC channel
#osamuko@irc.rizon.net - osamuko.com IRC channel (you are more likely to find mahjong talk going on here)
Mahjong message board for tournament coordination, discussion and whatnot

Index Top ChangeLog TODO License
Last updated: 2012-10-25