Source: http://blog.jpmahjong.net/read.php/621.htm
Lastly, we'll have an example to end this.
[The image with the K-ON background.]
In this situation, we're the dealer and the round is Ton 4 of a hanchan. We reached tenpai very early, and there are many choices to deal with this.
You can discard 2,3 pin and be in damaten/riichi or discard chun and declare riichi, but there is only one answer.
Damaten on the dora 3 pin might not be an easy wait either.
In addition, you should give up how the intermediate games' players think, like discarding 3 pin and declaring riichi to lure out 2 pin.
There are only two 2 pin left, the chances of winning is slim. Added to the fact that it is next to the dora, there is no one who would fall for such tricks in Houou level games.
You should only set traps when the chances of tsumo is low.
Discarding 2 pin and declaring riichi and tanki on the dora to bet on a tsumo is an extreme method. Tsumo gives you haneman and ura-dora gives you baiman.
If this is all last and you're behind by alot, you can play this way.
But in this situation, a tsumo mangan is more than enough.
Discarding chun here and declaring riichi should only be limited to this hand.
It's early and the chances of tsumo 1/4 pin is high.
And there's also a chance of having ura-dora 1 and reaching haneman.
(But in the actual situation, the other players all went into betaori after the riichi. orz)
