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My Discord server. Common mistakes (3)

Recently, I opened a new Discord server, with the purpose of having more quality discussions about the competitive aspect of the game. This is for people who want to improve and learn how to be as good as they can possibly be, and as such not recommended for people who just enjoy playing the game casually. If this channel caters to your interests, join us at: Competitive Riichi Hub

I should as well make it clear that I do not encourage dividing the current community in any way. The purpose here is only to create the best environment for players that want to get good, enabling them to get to a certain level as easily as possible. This Discord server is not associated with osamuko.com by any means.

Let’s go back to problem 3 at the previous Common mistakes (1) article.

2m3m7m7m1p1p2p3p3p3p4p4s5s Tsumo 1m

I told you that 3p is the correct choice here. Now, suppose you have this hand instead:

2m3m7m7m4p4p5p6p6p6p7p4s5s Tsumo: 1m (Dora unrelated)

6p is not always the best choice. In this case, if you want maximum speed, you should discard instead, because after discarding 4p, 3p is an useful tile. If you discard 6p, 3p would be useless.

Common mistakes (3)



What would you do in this situation?

Most of you should already know about defense, but let’s admit it, no one could grasp all the theories about defense written in all those guides in one or two go, and I’m not an exception. A lot of you would discard here because, well, it’s a reasonably safe tile and it does not destroy your hand’s development.

There’s a rule of thumb about defense that you need to remember: “When you are in 2-shanten or worse and facing a riichi, you have to defend in the safest way possible”. Except for desperate situations of course.

After discarding East here, you would still be in 2-shanten. Compare to an opponent who has already riichi’d, the chance for you to win against him is almost zero. And if you discard East, there’s still a chance that you would deal in. That’s why the correct choice must be ,a 100% safe tile. Suppose in the next turn you don't get a 100% safe tile, you should discard (This was in one of my matches back in 2014, and yeah, I discarded East back then too.)


Tsumo:  (dora unrelated)

is known to be a good shape, it's not a rare sight that people try to keep that shape and discard or here. However, it's a mistake.


You can see that after 1m, 5m or 7s discard, the number of effective tiles is the same, 16 tiles. However, if you discard , only drawing would give you a good wait tenpai (58s). If you draw any other effective tile, you would be in a bad wait tenpai (4m). The chance you get good wait tenpai is 4 out of 16. The same goes for , only drawing would give you a good wait tenpai. But, if you discard here, drawing either
or would give you a good wait tenpai! The chance is 8 out of 16. Since is a good shape, you don't need to keep the extra 7s. Instead, you need to keep your bad shape as good as possible, in this case, it means keeping shape. That's because keeping more tiles in the bad shape means you will have more chance to convert it into a set, leaving the good shape for your final wait.

Tsumo: (Dora unrelated)

Many would discard here because after that, we'd have the familiar great 1-shanten with pair, ryanmen and shape. Don't forget that, is also a good shape! You can turn this shape into two sets with , or .


If you discard , then is not useful anymore. There's four 8p left.

If you discard , then and are not useful anymore. There's two 6s and two 6m left, so you also lose 4 tiles. The number of useful tiles after 9p or 6s discard is the same, 19 tiles. However, after discard, all of the useful tiles that bring you to tenpai will give you Pinfu! After discard, drawing 6m or 6s won't give you Pinfu. That's why you should remember this situation and tell yourself to discard From now on. If in this example we swap 1m with 4m, then 9p is the correct choice because you need to secure Tanyao, though.