Chuuren poutou: Difference between revisions

|gameExample = * [http://tenhou.net/0/?log=2014020612gm-0029-0000-d32403e3&tw=0&ts=9 Chuuren]

* [http://tenhou.net/0/?log=2015082519gm-0009-0000-fde1c6c5&tw=2&ts=1 Junsei chuuren]

'''Chuuren poutou''' {{kana|九連宝燈}} is a [[List of yaku#Yakuman|yakuman]] and a specific instance of [[chinitsu]]. It contains the 13-tile pattern 1-1-1-2-3-4-5-6-7-8-9-9-9 of the same suit, plus any one more tile from the suit. In addition, the hand must be closed. Calling a [[kan]] on the 1 or 9 invalidates the yakuman.

A special pattern of chuuren [[tenpai]], '''junsei chuuren poutou''' {{kana|純正九蓮宝燈}} ("pure churren poutou"), results in a 9-sided wait. It occurs when you complete the 1-1-1-2-3-4-5-6-7-8-9-9-9 pattern without any duplicate tiles. Unlike the 13-sided [[kokushi musou]], this 9-sided wait is formed naturally with four sets and a pair. Some [[yaku variations|rule variations]] consider this a [[double yakuman]].

{{machi

|pattern  = 1112345578999p

|tilewaits = 6p

}}

If this hand wins with either of the yasume tiles, the hand will score only [[chinitsu]] rather than the yakuman.

{{machi

|pattern  = 1112345678999p

}}

[[File:9Gates.gif]] <!--http://en.wikipedia.org/wiki/File:9Gates.gif-->

In the above animation, the different winning tiles show the shifting tile group configurations as they count up 1 through 9. The groupings change with each winning tile. Sequential groups are marked in green, while the indicated pairs are marked blue.  Then in red, the 1 or 9 indicated as triplets.

==Development==

{{main|List of chuuren configurations}}

Since this hand is made up of one suit, it overlaps with [[chinitsu]] during development. In fact, many tenpai formations may result in chinitsu instead of the yakuman.

The key to this yakuman is the possession of ankou of both 1's and 9's of one suit. If two copies of either 1 or 9 are unavailable, then the yakuman becomes impossible. Similarly, if all four of any other numbered tile is unavailable, then it also becomes impossible. Of course, gathering a string of 2-8 is also difficult.