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 by any means.

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

 Tsumo:  (Dora unrelated)

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

 Tsumo:  (Dora unrelated)

Here, discarding  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.) (more…)

An awesome video guide from the internet. Common mistakes (2)

First of all, I want to show you a really good video guide that was created recently. The author is DdR_Dan, a player from US, who is staying consistently at 6d on tenhou, even got 7d in the past. Although it’s a little long, in my opinion it’s one of the best guides out there for 1-3 dan players, or even 4-5. Be sure to check out this and other videos on his Youtube channel too!


Common mistakes (2)


A lot of inexperienced player would feel that  is an isolated tile from the  sequence and therefore, discard it. That is a crucial mistake.

 should be interpreted as  + , which are two ryanmens, and the good discard here should be . After that, if you draw 4m/7m to convert 56m into a sequence, or 5m/8m to convert 67m into a sequence, you’d get tenpai with ryanmen wait!

The number of tiles that would turn   into one sequence and one ryanmen is 22 (four 4m, three 7m, three 5m, four 8m, four 4s, four 6s). Meanwhile the number of tiles that would turn  into one sequence and one ryanmen is only 12 (four 7p, four 4s, four 6s).


In this case,  and  should not be discarded. In the same fashion as the previous example,  should be interpreted as  + , two ryanmens. You can either discard 7m or 6s here (there’s a small difference between them but it should not be discussed here).

Players should remember  and  shapes. Discard the “leftover” tile from those shapes is usually a bad mistake. (more…)

Common mistakes (1), plus my introduction

Hey there, I’m starfire, a.k.a amaika on Some of you might have known me, some might not. I have played riichi since 2012. Now that I have become a decent player, 7d at the time posting this (even though I’m fully aware that I could drop back easily), and that the competitive part of the riichi community is not at a good state right now, I have decided to join the osamuko crew. My contents would definitely be not as good as xkime’s, but I hope that you readers can still find them useful! My posts will be written with the assumption that readers are familiar with the rules and common mahjong terms.

For my first post, I’d talk about some easily overlooked mistakes that are often committed by low-intermediate level players, including myself a lot of times.


 Tsumo: (Dora unrelated)

It is elementary mistake to discard  here.

New players only see pin tiles as  +  and  is leftover. However, in this case the pin tiles should be seen as  +  and  should be discarded, because your hand would now have Pinfu after 4p discard.

If you have something like , then the better discard choice would be , because you can’t have pinfu anyway, and two closed triplets give you more fu and the chance to kan. (more…)

Yaku, Hai!: Riichi (& Ippatsu & Daburu Riichi)

In order to be able to build the best hands, you need to know both how to plan out your play with a hand, and how to execute that plan. This is the essence of hand development: taking that group of 13 useless tiles you start with, and using them to build a tenpai that wins you the game. In riichi, you are constantly confronted with choices like “Do I open my hand?”, “Do I just try to get to tenpai quickly, or am I okay with a slower, more valuable hand?”, and the ever-important “Do I fold?” The yaku are basically your toolbox of techniques to build hands, so understanding each of them is critical (especially in games where they contribute more to scoring, like when playing without open tanyao or red fives).

This is the first article in Yaku, Hai!, a new series of articles which  go into detail on each of the yaku in turn, explaining the rules surrounding them, when you would use them, and the nuances which may not be apparent at first glance. This first article covers the single most important yaku: the titular riichi. We’ll also cover riichi’s brother double riichi and cousin ippatsu, since their the strategy is simply a part of riichi’s.

Riichi is simple on the surface: stay closed, get tenpai, declare riichi, profit! But both the rules and strategies are very complex, making it one of the most difficult yaku to master. Riichi is one of the best reasons to stay closed until you hit tenpai, but that’s not all. There is an incredible amount of strategy that goes into the decision of when to riichi or not, and there is far, far more than one article’s worth to say about it.


Identifying Dangerous Suji

Suji are a popular defense strategy; so popular, in fact, that suji traps are an effective anti-defense. We would like to increase the yomi level and create an anti-anti-defense by identifying when suji traps are likely. Are there situations in which suji are more dangerous? Are they really traps, or are they just incidental discards?

Prominent authors actually disagree on this. Some claim that suji discarded after riichi are more dangerous, while others claim that suji discarded before riichi are more dangerous. The general agreement is that the tile discarded immediately upon declaring riichi is dangerous.

Who’s right? Do you think there’s a difference? Using the Tenhou game logs database, we can examine riichi hands and their discards to finally answer this question.


Mahjong Keypoints: How to become the strongest, 1

Horiuchi AKA HoriiLast year I bought a bunch of Kindai Mahjong magazines and read through most of them. I skipped most of the manga and concentrated on the mahjong articles (yes, I am a bitter man, and you can sue me later). In one of my editions of Kindai Mahjong Original, Houou (Phoenix Rank) of the 27th Hououisen, and Fourth Dan from the Japanese Professional League of Mahjong, Horiuchi Masahito, who is known to have a strong background of digital mahjong and a steady win record thanks to his defensive technique, has written a few articles about mahjong. This is probably the only translation into English of something written by Horiuchi. Those who followed him last year during the live edition of Hououisen broadcasted in NicoNico don’t need an introduction for this person.


Basic Defense Techniques in Mahjong

Hi, tenpaiman here (aka TMN or TemporaryMobileName or whatever else I happen to prefer to be called on any given day). Today I decided to do a translation of a mahjong article by totsugeki touhoku [とつげき東北], author of the famous Kagaku Suru Ma-jan series of books on digital playing and statistics-based theory of mahjong, discussing defense, betaori, and all that important stuff. As a preliminary to this article, you should read up on suji and kabe, which is discussed frequently in this article and forms the basis of most defense techniques in mahjong. You can do so here.


Concealed vs Exposed

Tile efficiency works just okay for one’s own hand, but what about the tiles that flow out? Obviously, you shouldn’t call every single one of them, but that doesn’t mean you should ignore them either. How to judge? What to consider when calling? Well, the basics are sumed up in the following text.