WWYD 2014-03-27

[Ozball]

Here is the latest MFC みんなで何切る？. I'll post the Pro commentary for it when it comes out on the 7th of April.

[or2az]

So, it's East round only, 3rd hand, and i'm down by about 6000 pts. I like pinfu and tanyao along with riichi, menzen tsumo, and at least one dora, if I can draw the 8-crack. That's what I like! I'm seeing the hand as 34 456 67 5678 67 3.......... I would toss the and then the or the .

The would complete the chows while would get the pair.
Two appropriate tiles from the above eleven (one from each group) would mean tenpai with a ryanmen wait and then riichi. Lots of possibilities

That would be my game time quick decision. If I were ahead by 6000 pts, instead of behind, I would open the hand and go for the quick win, but i'm not, so I won't.

(I see the pairs of 44 and 66 already in the hand, but keeping the means a center wait, which i'm not crazy about, as this would prevent pinfu and limit my possible good draws from 11 "different" tiles down to 7, I think.)

[kfcbbq]

I'd definitely drop the to immediately bring myself into ii-shanten. , , , , , , are all viable tiles than can be called. There's still the possibility of a sanshoku or pinfu reach. But ultimately the goal here is to get into tenpai ASAP especially since I'm the dealer, and I wouldn't mind winning off even with a plain tanyao agari.

[Iapetus]

The iishanten has to be kept, so no sou or pin discards here. There doesn't seem to be much difference between 3467m since you need to discard two in the same suji to get to tenpai, and the end shape is effectively the exact same (44567m or 34566m). Time for micromanagement.

Discarding 4m or 6m is more efficient, since it leaves the 258m sanmenchan alive, giving the best path for turning the manzu into two mentsu and getting a pair in the souzu. 258m draw into 4/6m discard and 358s draw to excess sou discard are both very effective.

Of the two, 6m is better, since it leaves 7m in the final shape. 7m can be used to add in the 8m, getting dora and possibly 678 sanshoku. There's also a possibility of 567 sanshoku.

[Ozball]

I went with tsumogiri’ing the as my timed response, (ie treating it as if it was a game and making the discard decision within a reasonable timeframe) with the idea of going for Sanshoku in the 5678 range. We’ve already got 5678 in Bamboo, and the core of 67 in Dots, while in Craks we have the 67 core as well but also a 56 start meaning we can go either with 567 if we draw a and be left with a 67 wait, or 678 and be left with a 56 wait if we draw the . The 5 or 8 of bamboo will be discarded once we know which way the sanshoku will go, with the head most likely being the two 4-craks. We also have tanyao and most likely pinfu, so we could be looking as high as mangan or haneman, assuming we reach, depending if we get a dora for the sanshoku. My ideal shape for this hand would be 4455667 crak, 567 bam, 567 dot, discarding the 3 crak and 8 bam to get to tenpai.

Looking at it in more depth:
We’re currently in ryanshanten. Also it’s likely that South is building a Crak based hand, so we probably can’t rely on chi’ing any crak’s from them for a while. Also we likely have 1 run in dots and one to two in bamboos, leaving 1 to 2 in craks, also the head will most likely be coming from craks too. So looking at the possible discards:

First off I think we can rule out the . It doesn’t seem to achieve anything other than setting you back and likely putting you in furiten.
Also the bamboo’s other than the I think we can also rule out since if you’re not discarding the you’ll be wanting the other 4 to make up your two runs.

and might look similar at first glance but they are not quite the same. While they both drop us to iishanten, dropping the means we’re aiming for a head of and either a run of 567 or two runs out of 56 and 67, depending if whether we draw a before a crak to complete the runs. It also keeps the chance of a 67 core sanshoku alive. While tossing the gives a similar set up of a head and two possible runs in the 3445 area we lose the chance at sanshoku without really gaining much. The downside of aiming for two runs in craks is that one of the runs, either the 56 or the 45 will have a vastly smaller pool of tiles to use to complete it due to the head taking up two on one side and the other run taking up one on the other, leaving you with only 5 tiles out of a standard 8 for a ryanmen wait. Also the 34 run is further hampered by a having been discarded by the dealer, making the even less desirable than the .

and also drop us to iishanten. But again, due to using the one you didn’t drop for the head, the is less optimal as you lose your chance at sanshoku.

The I’ve already covered above.

The two dot discards I personally don’t think have any merit. You’re basically changing a ryanmen setup for a kanchan set up (67-dot for 35-bam) with no added benefit, and also the loss of a chance at sanshoku. And hoping the draw one of the other 3 or 2 seems like a downgrade since you can aim for either the 58-bam as your head which has the same number of tiles available but you don’t have to exclude one option. Or just keep the runs in dots and bams and use one of the readymade heads in craks.


In hindsight I think maybe the is actually the better option rather than my initial choice of the . Mostly because with my discard I’d be aiming to discard the at some point anyways, so it makes more sense to get to tenpai on the chance of drawing a . You still keep the ryanshanten for the ideal tanyao/sanshoku/pinfu/iipeikou, but also have the option to reach for tanyao/pinfu only if you draw the .

Iapetus: I’m trying to wrap my head around your idea. It seems so different to how I think of things that I want to be able to understand it. You’re saying that keeping the iishanten is of highest importance, which I can understand. I’m just confused since with the 6 (or 4) crak discard the only tiles that get you into tenpai are the , , and . None of which use two runs in craks which you seem to be aiming for, suggesting you’d need a second tile to be able to get into tenpai with two crak runs. If the next tile you draw is a 258 crak and discard the 4/6 crak to complete the two crak runs then you still need your head and you’re looking at a tanki wait if you draw a 5 or 8 dot. Drawing a 358 bam is nice as it sets you up for at least a ryanmen wait, and possibly a 3 way wait, but it only changes the shape of your iishanten rather than gets you to tenpai. I’m not suggesting this is wrong; I’m just trying to understand it.

Also kfcbbq: We’re actually West in this hand, not the Dealer. The red symbol is designating who was the starting dealer for the game.

[Iapetus]

Regardless of which manzu other than 5m is discarded, the hand gets the same iishanten. The point of choosing the 6m is that it is the best way to get a better iishanten. Generally, in iishanten priority 1 is to maximise the path to tenpai, and priority 2 is to maximise the path to a better iishanten (indirectly widening the path to tenpai, or increasing the score [thus increasing the expected value of the hand, which is what we're REALLY after with those tenpai path increases]).

So, here the best way to maximise the best path to a better iishanten is 6m for reasons I explained in the previous post. To summarise, 4/6m gives the widest path (258m wait), and 3/6m gives the highest score (dora/sanshoku), so the 6m that wins both categories is chosen (if the categories conflict, things get more difficult, but no such trouble here).

As to how drawing 258m improves the iishanten: at this shape, there's three types of tiles that lead to tenpai: 4s and 58m. But by transforming the manzu to two melds instead of a meld and a pair (for example, a 234567m35678s67p shape), the tiles that give tenpai are 3458s5678p - 8 types! A major improvement. The reverse works too. You yourself noticed that drawing 358s would be great. Drawing 67p first also improves the hand a tiny bit. Note that most of this still works no matter what manzu other than 5m is dropped, but 6m is just a bit better.

In general, shapes that have no set pair have wide paths to tenpai. For example, EEESSSWWN1289m only two tiles to tenpai in 37m. But EEESSSWWW1289m has 6 in
123789m. Aiming for "headless" shapes like this is very often a good move. There is a risk of ending up with a bad tanki wait, though. For example, 234567m1178p56sW has 16 tiles to a ryanmen tenpai. 234567m12378p56s has 28 tiles to tenpai, but only 12 of them give a ryanmen while 16 give tanki. However, this is only really bad if all you have is a pinfu nomi and don't want to tanki riichi. And even then, tanki waits often imrove easily to nobetan and such. (As for the WWYD we are talking about, that isn't a concern because the souzu are a bad meld wait in kanchan 4s, but a good pair wait in 58s nobetan.) There's also the possibility of an ankou backup - for example 234567m11178p56s has 26 tiles to tenpai, all of which give ryanmen! The moral of the story: if there's a chance to transform your pair to a meld, do it! And if you have nothing else to improve, maximise your chances of transforming it!

[Ozball]

I'm a little annoyed at myself. I checked my MFC page mid week and realised I hadn't put my answer in yet, so figured I'd input my new answer of instead of my old one. And well... Here's the results and Pro response:

Popular response:





Pro Response:



"Discarding the is the straightforward method, however it’s the second last hand and I don’t feel that only tanyao would be enough. With this hand you want to aim to setup a big hand that will get you into first in one go. Therefore I would cut the , and, if I’m able to, complete either a tanpin sanshoku, or a tanpin iipeikou hand. Cutting the means it’s east to create the shape you want, and even if the yaku falls apart it’s still easy to reach with. While cutting the also allows you to aim for a 678 sanshoku, the flexible shape you get from drawing craks has more merit I think than drawing a or ."

Shirakawa Yukina Pro - 2nd Dan

Vocab:
Tanpin = Tanyao (All Simples) and Pinfu (Peace)


Four Gods Distribution: (I don't really know what else to call this one)




I should stick with my gut reactions more -.-