Tenhou.net rules

The following is a translation of the rules used in Tenhou.net.

The rules

• Start with 25000 points; Players must return 30000 points
• Uma 10-20
• Atozuke ari
• Kuikae nashi
• Kuitan ari or nashi option
• Red dora ari or nashi option (1 5m, 1 5p and 1 5s)
• Noten dealers lose the dealership. Known as "tenpai renchan".
• Sudden death brings the game into the next wind. As soon as someone attains 30,000 points (riichi deposits are removed from players' scores), the game ends.
• Sudden death must end at South 4 for tonpuusen, or by West 4 in hanchan.
• Busting enforced. Scores below zero stop the game, nagative points are included in the point tally.
• In all-last hands, if the dealer is winning, the game automatically stops on both dealer wins and dealer tenpai hands.
• At the end of a game, points are rounded to the closest thousand, "4 down, 5 up".
• At the end of the game, riichi deposits go to 1st place.
• At the end of the game, if there is a tie, the tie is broken in favor of the person having the earlier dealership.
• A pair of a double wind is worth 4 fu.
• Winning with the rinshan tsumo tile is worth 2 fu.
• No 2 han minimum rule. Hands always require a 1 han yaku or better.
• Abortive draws (Nine terminals abortion, four riichi calls, three ron calls, four kans (separate), four same wind discards) allowed. All count as renchan.
• Nine terminals abortion requires 9 or more different terminals, on the first turn before any pon, kan, chii calls or ankan formed.
• Nagashi mangan allowed. Tenpai payments are replaced by the mangan payment. Dealer tenpai counts as renchan.
• Double rons allowed. Repeats and deposits go to the next closest player.
• Double rons occuring with the dealer winning are counted as renchan.
• Pao is enforced on daisangen and daisuushi. Multiple yakuman still count. Tsumo win = responsible player pays all, ron win = responsible player pays half. Related repeats also paid through pao.
• No pao on suukantsu.
• Keishiki tenpai ari. Your tenpai may include a wait for a "5th tile" (however, this does not include the case when the 4 available tiles for said wait are included in your hand).
• You need at least 1000 points and a next turn to pick (4 or more tiles in the wall) to declare riichi.
• If the tile that was used to declare riichi is won off, no deposit is given out. //リーチ宣言牌で放銃した場合は供託料は発生しない
• Furiten riichi allowed.
• After riichi, letting a winning tile pass makes your hand furiten.
• リーチ後の縛りをクリアしない和了型になる牌は常に見逃し、以降振聴
• Ankan that changes the wait tiles after a riichi is prohibited. Okuri-kans are not allowed. Ankans that do not change your wait are allowed.
• Kan dora and kan ura dora allowed.
• Kan dora are flipped as follows: from ankan immediately, from minkan and from kakan are shown after discarding or picking a new replacement tile.
• 純正巡消しは発声＆和了打診後（加槓のみ)、嶺上ツモの前（連続する加槓の２回目には一発は付かない）
• You may not selectively ron a player in one turn (includes chankan) - i.e. if you pass a winning tile dropped by one player in one turn, you may not ron from another player who discards the same tile in that turn.
• Same-round furiten removal is at discarding a tile, claiming a tile in the reverse order does not remove it. // 同巡振聴の解消は打牌時、逆巡副露では解消しない。
• The last tile discarded cannot be called.
• No Paarenchan, renhou, sanrenkou, iisou sanjun, shiisan puta, etc. (local yakus)

External links

• Tenhou manual page (Japanese)