Ippatsu: Difference between revisions

It is awarded if the player receives a winning tile within an uninterrupted set of opponent tile draws after the riichi declaration. The earliest possible chance to win with ippatsu comes from the shimocha's discard (player to the right).  The latest possible chance to win with ippatsu is with the player's next drawn tile after the riichi declaration.  

In order for ippatsu to be counted, the hand must win before the hand in riichi discards its next tile.  Furthermore, no interuption to the turn must occur.  [[Naki|Tile calls]] may immediately end the chance for ippatsu any time before the riichi declarer draws the next tile.  This includes any calls for [[kan]], except for a robbed kan ([[chankan]]). In [[sanma]], the call for [[kita]] also interrupts and thus denies ippatsu.  Even if the hand wins before the next tile draw, ippatsu does not count if a tile call was made previously.  Thus, players may actually use the option to make tile calls to deliberately deny a player that chance for ippatsu.

Ippatsu is unique among the yaku, for it requires riichi to even be applicable. Because of this, it is impossible for a hand to score with ippatsu alone. Ippatsu ''can'' combine with [[chankan]], as the kan call is not considered complete if someone wins off it.

At the very minimum, a hand could be riichi with ippatsu.  Unlike riichi, ippatsu is not compatible with every other yaku.  Two cannot mix with ippatsu: [[rinshan kaihou]] and [[houtei raoyui]].

Regarding rinshan kaihou, the required call for [[kan]] to invoke rinshan already cancels out ippatsu. With one single tile left in the regular wall, the last chance to call kan is allowable.  This may imply the rinshan draw as the "last possible tile draw".  However, that tile came from the dead wall as opposed to the regular wall, which is not the definition for the haitei.

 

As for houtei, a riichi declaration must be made with at least 4 tiles left in the live wall.  That leaves the very last possible tile draw (and discard) belonging to the riichi declarer.

The last possible chance for riichi comes, when there are eighteen tiles left in the walls.  This counts the dead wall after a tile draw. So, that leaves four tiles left for regular player draws; and barring any tile calling, every player would then have only one tile draw left. For haitei then, the fourth remaining and last tile tile draw goes to the riichi caller. Naturally, tile calls may occur beforehand to deny both the ippatsu and haitei chance.