xGeo's Mahjong Blog

Experiences with Japanese Mahjong


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Yaku Lists

Happy New Year!

As a way to finish up the year, I am going to upload the yaku sheets that I have made in the last couple of years. They are by no means entirely complete, but anyone with some exposure to mahjong terminology and yaku should be able to understand them. I will go over scoring in depth in a future post, but take a look at these packets for now. I have 2 versions: one is an excel sheet and the other is a word document. They contain the same information but formatted differently.

1. The Excel sheet

Japanese Mahjong

2. The Word document

Yaku

3. Yaku list on Osamuko (has pictures!)

http://osamuko.com/yaku-overview-pdf/

Feel free to use these as you like. If you have any suggestions or corrections, let me know.

As always, thanks for reading and have a great 2016!

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25 Days of Yaku: #25 Chinitsu

Last one! Merry Christmas!

The Basics: Chiniisou (清一色) or Chinitsu (清一) is a yaku worth 6 han closed and 5 han open. It is for hands that contain only one suit and thus is often referred to as a full flush (with half flush being honitsu).

Thoughts: Chinitsu is the most expensive yaku in the game outside of yakuman. For an open hand, it is already a guaranteed mangan and haneman for a closed hand. When you go for an open chinitsu, it is easy to bump it up to haneman with things like dora, tanyao, or ittsuu. Chinitsu hands are often very complicated. Be extremely careful to not end up in furiten or make calls that do not advance your hand. To practice this, I recommend trying Bamboo Mahjong. This is a two player game that only involves one suit. To check youself, you can use the Tenhou Tile Calculator. Just enter what your hand is and it will tell you your wait if tenpai or tiles that will advance the hand. Although chinitsu hands do not come frequently, be sure you are familiar with one suit shapes so you are not hesitating too much when you play. It may backfire as you may miss tiles, make inefficient calls, and let your opponents know what you are up to before your discards give you away. It is usually obvious when people go for chinitsu because their discards lack one suit. Once a tile of the suit they are aiming for overflows from their hand, you should be very cautious as dealing into a chinitsu hurts a lot.

With this, the 25 Days of Yaku has ended. Thank you for reading! I will make a post with my yaku sheets soon.


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25 Days of Yaku: #24 Shousangen

The Basics: Shousangen (小三元) is a yaku worth 2 han. It is often called “Three Little Dragons” in English. To get shousangen, a hand must have 2 sets of dragons and a pair of the third. If a hand has 3 sets of dragson, that is called Daisangen (大三元) or “Big Three Dragons” which is a yakuman. Shousangen may be scored for open or closed hands. Sometimes you may see shousangen listed as worth 4 han. This is because shousangen is effectively 4 han since it is worth 2 han and you get 2 han from two yakuhai sets.

Thoughts: Shousangen is really rare and generally a very expensive hand. With a guaranteed 4 han, it’s value can exceed mangan and rise quickly. It combines well with other yaku, honitsu and toitoi for example. People usually don’t aim for shousangen. Usually they aim for daisangen first, realize that it’s not feasible and then settle for shousangen. There really isn’t much strategy with this yaku. If you have pairs of all or most of the dragons, then hope to pon them or pair up single tiles if you have them. If you see someone pon 2 dragon sets, be wary of the third dragon.

That’s it for today. Thanks for reading and Merry Christmas Eve!


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25 Days of Yaku: #23 Ryanpeikou

Ryanpeikou doesn’t sound like the name “Ryan.” Just how romaji works…

The Basics: Ryanpeikou (二盃口) is a yaku worth 3 han. It is awarded to hands containing two sets of two identical sequences. Recall iipeikou and see that ryanpeikou is simply having 2 sets of iipeikou. Also note that ryanpeikou only applies to closed hands, so no calls may be made.

Thoughts: Ryanpeikou is a very rare yaku as there are many things that must go right for it to happen. Sometimes you may win only with pinfu and iipeikou while going for ryanpeikou because one set may be completed on the wrong end. Something important is that ryanpeikou cannot be scored simultaneously with iipeikou or chiitoi. (A ryanpeikou hand will have 7 pairs which can be rearranged as sequence sets.) You should score a hand as ryanpeikou rather than chiitoi because ryanpeikou is worth 3 han while chiitoi is 2 han. Also sequence hands have the potential for pinfu.

Almost to the end! Thanks for reading!


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25 Days of Yaku: #22 Honitsu

The Basics: Honiisou (混一色) or Honitsu (混一) is a yaku worth 3 han for closed hands and 2 han for open ones. It is for hands that contain only one suit plus honor tiles. There must be honor tiles in the hand. Otherwise the hand will contain the yaku chinitsu (all one suit) instead.

Thoughts: Honitsu is a very common yaku and can be worth a decent amount. (In 3 player mahjong, it is extremely prevalent.) It combines well with yakuhai, ittsuu, chanta, and toitoi. There are more options when closed like iipeikou, sanankou, and chiitoi. (Of course honitsu can be combined with other yaku.)

It is usually fairly obvious when someone is going for honitsu. You will be able to see a lack of one suit in their discards. If they have called tiles already, you will have to be cautious of yakuhai and tiles of the suit they want. Often people are more likely to go for honitsu in the same suit as the dora, so be extra careful when this is the case. I notice that people are often tempted to go for honitsu very frequently. Obviously honitsu is viable when you start with a lot of tiles of one suit. However one should still consider what the other tiles are. If you have good ryanmen shapes (two-sided waits), then honitsu may be slow unless you call. If you intend to go for honitsu, you need to get rid of your dangerous tiles of other suits (especially dora and middle tiles) early on. Otherwise you may deal in later.

That’s all for today! Thanks for reading.


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25 Days of Yaku: #21 Honroutou

Today’s post concludes the section on terminals and honors yaku.

The Basics: Honroutou (混老頭) is a yaku worth 2 han for a hand composed of only terminals and honors. This means that only triplets and pairs of terminals and honors can be used for the hand. Thus with 6 types of terminals and 7 types of honor tiles. Only 52 tiles can be used with 13 distinct sets. Honroutou can be scored by both open and closed hands.

Thoughts: You may be wondering why a special yaku like honroutou which is pretty hard to get is only worth 2 han. This is because honroutou implies either toitoi or chiitoi which is another 2 han. When looking at junchan, we noted that while chanta encompasses junchan, both cannot be scored at the same time. Be sure to note that this is a different case where honroutou can be combined with toitoi/chiitoi. In addition, honroutou will combine with yakuhai very easily. There are 5 valid yakuhai for a given player (3 dragons, seat wind, round wind) so honroutou can be boosted by 4 han or 5 han (if seat and round wind are the same) from yakuhai. While Japanese Mahjong emphasizes closed hands, honroutou can be very valuable even when open. Therefore it is fine to open your hand to win faster. However don’t be surprised if your opponents catch on after you call.

Honroutou

Now that we’ve covered honroutou, you will understand the joke (from Fushigi no Kuni no Miyuki-chan)


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25 Days of Yaku: #20 Junchan

Almost to the end! I’ll briefly talk about terminals today!

The Basics: Junchantaiyao (純全帯么) or simply Junchan (純全) is a yaku worth 3 han closed and 2 han open. The condition is that every set (and pair) must have a terminal in it. That means the the sequences 123 and 789 can be used along with triplets of terminals. Junchan is basically the upgraded version of chanta. Note that you cannot score chanta and junchan at the same time as it is redundant. A hand can be chanta, junchan, or neither and never both.

Thoughts: As junchan can be worth 3 han, it tends to be expensive when closed. Often junchan is combined with sanshoku or iipeikou. A closed junchan sanshoku is already mangan. With dora, iipeikou, and pinfu, there is haneman and baiman potential without riichi. If you need a comback and have a hand for junchan, consider going for it. It requires good draws to be closed as you will have the same problem of edge waits and closed waits like with chanta but it will be harder since there are less tiles to work with (72 tiles of 18 types).

Since junchan tends to be a slow hand, it is fine to call for it since it is still worth 2 han by itself. Just be sure that if you end up on an open wait, you do not get into furiten. A 4 or 6 could make the hand entirely worthless. If you riichi with a junchan tenpai that has a 1,4 or 6,9 wait, it is not guaranteed for this reason.

Thanks for reading and sorry for the delay!