/ Tenhou Review

Game Log 9

Date: 17/08/81
Game Type: 特南喰赤
Link: http://tenhou.net/0/?log=2017080314gm-0029-0000-a36679dd&tw=1
1位 B:Dasuke(+40.0) C:AFRO(+10.0) D:ちりりーん(-19.0) A:あららんよん(-31.0)

E1-0 17th Turn

The "RUN FOR YOUR LIFE" kinda of situation.
Dealer declared riichi, shimocha Immediately declares Kan and 4 turns later declares riichi. As safe tiles have dwindled down to nothing, what should I discard to avoid East 1 obliteration?

As always lets look at the available shapes that can be waiting on the tiles in my hand, with exception of the tiles around the dora (3m->9m). 1m has 3 ryanmen chances, 2p has 1, 3p has 1, 5p has 1, 6p has 3, 0s has 1.

Looking at the cases with only a single ryanmen remaining I got 2p,3p,5p, 0s left over. 0s seems particularly precarious due to the 6s riichi declaration tile from the dealer, but is a genbutsu on the other side. 3p looks pretty ok shape wise (only 24, 3, 33, and 45 once chance possible) but tanki or shabo is higher than 2p and 5p since 3 are missing from my sight. Finally 2p and 5p both have two seen tiles, and are both a one chance for ryanmen. The shapes remaining for 2p are 34 once chance, 2, and 22 one chance. The shapes remaining for 5p are 34 one chance, 46one chance , one chance, 5, and 55 one chance. While 5p does have the adcantage that if the first one passes and I don't get a safe tile next turn I can drop the other one, its disadvantages are it has one more waiting shape than 2p, and more importantly is still out of sight as well. The called 7p by toimen happened After the riichi, so there's a decent chance shimocha has tiles surrounding their discarded 4p. That being said, in my opinion 2p slightly wins out here.

E3-0 11th Turn:

Another defense question, WWYD?
Here I think I kind of messed up... With no defenive tiles and two riichi in bound, this hand only has a prayer and a one chance to go off. While 2m is suji for both players, a 5m riichi by the dealer could very easily come from a held to the last minute 135 shape. In general, the suji tiles of declaration tile or Right before it have a higher waiting chance than suji tiles presented at other times. Considering that, the choices are down to 4s nakasuji, as well as 4m one chance. Generally nakasuji would have a lower win chance between the two, but in this case the missing tiles surrounding the 4s are pretty consierable. Furthermore the 4m is safe for toimen and could only reasonably waited on via the 06m shape from dealer. So my choice for this is the 4m once chance.

Now the reason I said I think that I messed up here is not due to this discard, but passing on a called tile. Considering the defensive capabilities of this hand, little to none, while a safe turn is desired I'm in a pretty tight spot. conisdering that, it might actually be Better to risk a single no suji through and have tenpai, than it would be to fight to the death with the little information I have for no gain. A quick win is also a defensive options at times.

E4-1 10th Turn

It's written in a number of Mahjong books and guides that waiting for a hand upgrade is worth it if it can give you 3 or more han. So in this case, is it worth it?!
The quick answer...No. While it is true it can be advantageous to hold back on riichi in the case you can get a 3h+ hand upgrade, there are a number of limits to this. The first one is Time. Considering how late in the game we are at this point, there is a lower possibility at a successful upgrade, lowering the average worth of the hand by taking that route this late in the game. The second thing is the Mangan Limit. With each new han, hand values Double in score all the way up until they hit a Mangan. At that point it takes TWO han to jump to the next level, which only goes up 1.5x, and after that another two han to the next level for 1.3cx, three for the next level for 1.5x, and 2 for the final 1.333x increase. Compared to the one han for 2x trade off, the other improvements are pretty lack luster in comparision. Considering that this hand already has pinfu dora one, especially this late, take the immediate riichi!