World Riichi Championship rules
The World Riichi Rules consist of combined rulesets applied by the EMA and contemporary Japanese rules. The rules document is authored by Sylvain Malbec and is accepted by the EMA, JPML, and the rest of the tournament participants. The rules were applied to the 2014 World Riichi Mahjong Competition.
Summary
The rules apply regular Japanese mahjong rules with some notable differences.
Kazoe yakuman
Normally, a hand worth 13 han or more is classed as a yakuman. However, this value is reduced to sanbaiman.
Tochuu ryuukoku
Abortive draws are completely omitted from the tournament.
Uma
The uma for the tournament uses 「+15 / +5 / -5 / -15」. However, in the event of a tie between players, then the uma is adjusted to accommodate the tie. At the end, the end game score is calculated as follows:
Session score = ((points – 30,000) / 1,000) + uma