Beginner's Lesson 11
In this lesson, we will cover 2 new yaku, based around single-suit hands.
The first yaku is honitsu. Honitsu requires all of the number tiles in the hand to be from the same suit and may include honor tiles. Honitsu is worth 3 han.
The second yaku is chinitsu. Chinitsu requires all of the tiles in the hand to be from the same suit; tiles from the other 2 suits and honor tiles are not allowed. Chinitsu is worth 6 han.
You may have figured out from the earlier minigames, but having a lot of tiles in the same suit can make the shape of the hand very complex. You might have to rearrange the tiles in your hand to figure out what tiles you need to complete the hand. This takes practice, but there are a few tricks that could help narrow down the exact shape of the hand.
The main thing is to pay attention to any ankou in your hand. These could be used as a triplet by themselves, but they could also be used as your pair, leaving the third tile of the ankou to be used with other nearby tiles.
A simple example would be a shape like 4445. If you consider the 4s as a triplet, then you need another 5 to complete a pair. But if you consider the 4s as your pair, then you have a ryanmen wait with the 45, waiting on 3-6. These sorts of complex patterns can appear in other hands, but they are much more likely when your entire hand is the same suit.
Also pay attention to any sequences around an ankou. A shape like 4445678 is actually waiting on 5 different tiles. If the 4s are used as a triplet, then the remaining shape, 5678, is waiting on either a 5 or an 8 to complete a pair. If the 4s are used as the pair, then the remaining shape, 45678, is a 3-sided wait on 3-6-9, like 2 overlapping ryanmen shapes.
Understanding the shape of a single-suit hand can be very difficult, so do not be discouraged.
Here is a video explaining these yaku by Light Grunty:
Honitsu and Chinitsu
Honitsu and chinitsu do not allow combinations with hands that require multiple suits, like sanshoku. However, they can be combined with most yaku that we have learned up to this point. Both honitsu and chinitsu can be combined with yaku like pinfu, ittsuu, toitoi, and chanta. Honitsu hands commonly have yakuhai, though chinitsu hands cannot. Chinitsu hands can also qualify for tanyao, though honitsu hands cannot.
In the next lesson, we will cover the namesake of riichi mahjong, the most common yaku, riichi. We will also discuss another aspect that sets riichi mahjong apart from other styles, dora.