Just a quick note to let you know that I´ve made a couple of guides which are now hosted on GameFAQs. They´re specifically intended to support people playing the PS3 game Mahjong Taikai IV but they could prove useful to anyone playing MJ.
http://www.gamefaqs.com/console/ps3/game/930074.html
The main guide is a plain-text file which is a full guide to the PS3 game. The section on \"custom rules\" might be of interest as it explains twenty optional rules in Japanese MJ. In writing the guide I´ve tried to include as much Japanese terminology as possible too (although I do use the terms chow, fan, etc - sorry!).
Alongside this is an image file which lists mahjong-related Japanese text which could be helpful for anyone who´s just started playing MJ with Japanese software.

(removed direct image link since GameFAQs is blocking it :S - use link above)
I´m still quite new to both mahjong and reading Japanese so I´d welcome corrections or contributions to both the game rules and my efforts at translating. I can also send an uncompressed version of the gif on request.
You can email me at [my username] at hotmail.com or just follow-up in this thread.
Thanks. B)
Bart
PS I´ve just started writing a guide for Mahjong Fight Club (PS3 version) but from past experience it could take a few weeks or months... Stay tuned!