Author Topic: Tiles of the Unexpected #1: Kan after riichi results in chombo penalty!  (Read 2475 times)

0 Members and 1 Guest are viewing this topic.


  • Author
  • Administrator
  • Sr. Member
  • *****
  • Posts: 331
    • View Profile
    • My book: Mahjong from A to Zh
Just finished a great match, and my opponent, DC_Black, thought that after declaring riichi he had won with a kan supplemental tile. I hated to break his heart, but he actually ended up owing a chombo penalty because his kan had changed his tenpai pattern in a very subtle inadvertent way... check it out:

You can only declare a concealed kan after declaring riichi if:
1. The tile adds to a concealed pon already in the hand.
2. Making the kan will not change the formation of the sets in the hand.
3. Making the kan will not change the tenpai pattern.

His waiting hand was this...
:c3::c4::c5:  :d6::d6::d6:  :d7::d7::d7:  :d8::d8:  :north::north:

He was in a double-pon wait for either an 8-Dot or a North tile.

BUT a less obvious way to assemble this hand, and thus a less obvious tenpai pattern, has this hand also waiting for a third identical chi...
:c3::c4::c5:  :d6::d7::d8:  :d6::d7::d8:  :d6::d7:  :north::north:

So when he drew a fourth 6-Dot, his best move would have been to discard this dangerous tile, because in choosing to use it to make a kan of 6-Dots, he inadvertently also eliminated his hand's wait for the third identical chi (which needs all three 6-Dots from his original hand), and thus in the process also inadvertently changed his hand's tenpai pattern.

So even though his kong-supplimental tile just happened to be a winning tile...  a third North tile... instead of winning with a kan-supplimental tile... he ended up paying a chombo penalty to all the other players for changing his tenpai pattern after declaring riichi!


But a great lesson worth posting.


While this post started in the Japanese Riichi forum, I decided I will start posting lessons learned like this one for players to read and improve their game. For now, a working title for this new thread of posts will be "Tiles of the Unexpected", but if I think of something better, I may change it.

MASTER LIST OF LESSONS: Tiles of the Unexpected
« Last Edit: January 27, 2013, 11:58:15 pm by SDMiller »


* Osamuko's RSS

Invalid feed.