Mahjong Fundamentals 4: Yaku and Value

Tile efficiency is important for winning hands, but for most mahjong players what they really want to do is to win games. To win a hand, you just need to be the fastest person to complete your hand, but for winning games, the value of the hands you win starts to matter. Value is an important consideration because of the way scoring works in riichi mahjong, and the fact that hands increase sharply in value over the first few han. Someone who wins six hands all at 1000 points each can be quickly overtaken by someone who wins just a single 8000 point mangan hand.

Players who just chase fast and cheap hands may win a lot of hands, but it’s unlikely that they’ll win a lot of games, because it’s usually far more effective to win less often, but with more valuable hands when you do.

A good rule of thumb is to try and aim for 3 or 4 han at the start of each hand (so above 3900 points). This isn’t always possible, and sometimes you just have to take what you can get, but getting 3900 point or mangan hands is the cornerstone of winning hanchan (East and South round) games.

Which Yaku Should I Go For?

This is a common question for beginners. The real answer to this question is “Whatever your hand lets you go for”. Most of the time your hand chooses your yaku for you, and building value largely becomes around trying to get to tenpai quickly whilst picking up whatever you can on the way. Players usually have their own favourite yaku, but trying to push every hand towards a specific one you like is unlikely to win you many games. The key thing is to be mindful of which yaku exist, and to make sure you don’t carelessly throw value away as you build your hand.

There are around 20 different yaku in riichi mahjong, not including yakuman, and trying to remember all 20 and work out if your hand can make them is a lot to think about. Luckily the majority of these yaku are either rare, or are variations of each other. Let’s go through the most important ones that you can go for:

Riichi

Riichi is one of the most important yaku, and is also the most common (around 30-40% of all winning hands have riichi). The key thing for riichi is that it is always a valid option to you at the start of a hand – so long as you keep your hand closed you can pretty much always aim for riichi. We’ll cover riichi and the pros and cons in more detail in the next article in this series.

Tanyao

Tanyao (all simples) is another very common yaku in riichi mahjong, seen in just over 20% of winning hands. Tanyao is common partly because the requirement is quite easy to get (hand must not have any 1, 9, or honour tiles) and in most rulesets can be open or closed, and partly because tanyao synergises well with tile efficiency.

As we have seen from the previous articles, honour tiles and terminal tiles are less useful for tile efficiency, and are typically the preferred discards early in the hand when considering efficiency. Because of this, quite a lot of hands end up as tanyao just by coincidence when discarding for maximum efficiency.

Pinfu

Pinfu is a somewhat complicated hand in terms of the requirements to get it. Your hand must be closed, must be four sequences and a pair, and your final wait must be a two-sided ryanmen wait, and your pair cannot be a value honour tile. Despite the convoluted nature of pinfu, it is a very common yaku, with just under 20% of all winning hands containing pinfu.

The reason for pinfu being such a common hand is that it has powerful synergy with tile efficiency due to the insistence on sequences and a final ryanmen wait. For hands where we do not want to call tiles and open our hand, efficiency will very often lead us towards two-sided ryanmen shapes and therefore towards pinfu. Because they will be tenpai with a strong ryanmen wait, and insist on being closed, pinfu hands are very good hands to riichi with, especially if they have one or two additional han through dora or yaku such as tanyao. Unless there is a very exceptional reason not to, we should almost always riichi when we reach tenpai with pinfu hands.

Yakuhai

Yakuhai, also commonly known as fanpai, involves having a triplet of either your own wind, wind of the round, or a dragon tile. A yakuhai triplet is one of the easiest ways to get an open hand that will definitely have at least one yaku for the win condition.

It is worth noting that yakuhai on its own gives a very cheap hand, and it’s usually not worth pursuing a hand that is solely yakuhai. Typically it is best to aim for this hand and call aggressively when your hand has two or more han from elsewhere in the hand, such as from honitsu (half flush) or dora. Especially given that honour tiles tend to be discarded early into the round, it can often be better for a yakuhai-only hand to let the first discarded tile pass and see how the hand develops, keeping the pair of honours as either your pair, potential safe tiles, or waiting to call on the 4th honour tile if it comes out later.

Honitsu & Chinitsu

Honitsu (half flush) and chinitsu (full flush) are common yaku based around your hand containing tiles from only a single suit, with or without honours. Honitsu is quite common, with chinitsu being a lot rarer but also worth a lot more. As with yakuhai, these are yaku that often require you to open your hand, however can also allow you to call aggressively if you need to in order to reach tenpai.

Chinitsu is always a guaranteed mangan minimum, and so has very good value. Honitsu on its own is typically quite weak, and I would not recommend forcing a hand too hard if it is only honitsu, as two han for an open hand is still a bit cheap. However, if you can pick up one or two additional han from dora or yakuhai, then honitsu can be a very strong open hand.

One thing to be wary of with these yaku is that they are usually quite obvious and easy to defend against, especially if you call multiple times. Against good players it should be expected that people will stop discarding tiles of the suit you need towards the end of the hand, and it’s important not to chase honitsu or chinitsu with a hand that starts too far away and requires too many calls or lucky draws. Ideally you should be able to at least see how the five blocks of the hand are going to form (either from groups of tiles or at least loose tiles) before committing to pursuing these yaku.

Iipeikou , Sanshoku & Ittsuu

Iipeikou (two identical sequences), sankshoku (same sequence in each suit), and ittsuu (straight 1 through 9 in one suit) can be quite easy to overlook, but are very useful for building value into a hand. Both ittsuu and sanshoku have the benefit of being available whether open or closed, and sanshoku can be quite difficult for opponent players to detect and/or defend against.

The key with these yaku isn’t necessarily to pursue then strongly, but to at least be mindful of them and keep an eye out for the possibility of them forming in your hand. For example, in circumstances where your hand has , and loose and tiles, it may be better to keep the tile to keep the potential for sanshoku open, even though has slightly better tile acceptance.

Chanta & Junchan

Chanta (terminal or honour in each group) and junchan (terminal in each group) hands revolve around having terminals in each meld, which means they have very poor synergy for tile efficiency as you cannot form double-sided wait protoruns with this hand (or you can, with 78, but you will lose the yaku if you draw a 6). Both of these yaku can be quite difficult to get with a closed hand, and are usually fairly obvious to your opponents as you will end up discarding a lot of middle tiles from your hand early. Typically, I would recommend that you don’t pursue these yaku unless your hand shape really pushes you into them.

On the positive side, both of these yaku leave your hand with reasonable defensive ability, as you will tend have a greater number of safer tiles if things start to look dangerous and you need to fold. It can also be awkward for opponents to defend against you, as it will involve keeping edge tiles that they would most likely prefer to discard from their hands

Chiitoitsu, Toitoi & Sanankou

All of these hands have very poor synergy for tile efficiency, because they push the hands towards shapes that are bad for tile acceptance. As a result they can be quite situational, and are typically hands that you find yourself having to go for because of what you draw, rather than by choice.

For chiitoi (7 pairs), it is important to bear in mind the flexibility that the hand can have in terms of the final wait – in particular chiitoi is very strong when combined with riichi if you can wait on a tile that appears relatively safe to your opponents (such as a valueless wind). Chiitoi is an OK hand to pursue if you find yourself with multiple pair shapes in your hand, and no or very few ryanmen shapes.

For toitoi (all triplets), you should ideally have some other value within your hand, be it dora, yakuhai, or honitsu. This is because toitoi typically requires you to call multiple times, and can quite often leave you in a situation with very little defence if someone else declares riichi. If the hand is only toitoi (usually 2600 points as non-dealer) then the low value often doesn’t justify the slow speed and high risk of opening the hand to call tiles, and it’s typically better to try and shift the hand into a more normal shape.

Sanankou (three closed triplets) is not usually a yaku to specifically pursue by passing calls unless you really need the additional value or have no other yaku, as it is quite unlikely when you have a pair than you can pass on the third tile and draw the fourth yourself. It is worth noting that sanankou is only valid if all the tiles in all three triplets were drawn by you – having two closed triplets and calling ron on a discard to complete the third does not qualify.

Dora

A key component of riichi mahjong is the dora. Dora are not strictly a yaku (and do not satisfy the requirement of having a yaku to win) but are incredibly powerful in terms of their ability to rapidly increase your hand value, and it’s important to make sure you stay aware of what the dora tile is for the duration of the round. In particular make sure you know what the dora is before you make your first discard – this is something beginner players often forget to check and it’s a very easy way to throw value out of your hand, and possibly into someone else’s!

Typically it is a good idea to hold onto dora as long as possible (unless doing so would cause you to lose a different yaku, such as tanyao with a terminal dora), and for the early stages of a hand it is also beneficial to hold onto tiles that are close to the dora, with the aim of keeping your hand able to accept a dora tile if you happen to draw one.

Other Yaku

There are a few yaku that I’ve not included in this list because they are more things that happen through luck, such as menzen tsumo (fully closed and win by tsumo) and ippatsu (win before your next discard after riichi). It’s important to know these yaku for scoring, and they are very common, but they are not typically yaku that you can specifically aim for.

There are a number of other yaku such as ryanpeikou (two sets of two identical sequences), sanshoku doukou (same triplet in each suit), and the yakuman hands, that I’ve not included in the list. These are quite rare, and typically aren’t worth having too much consideration for. It’s worth being aware of them for when they do happen, but coveting rare hands too much tends to lead to a lot of inefficient mahjong play and wasted hands.

Open Hands vs Closed Hands

The decision for when to open a hand or keep it closed is a common one in riichi mahjong, and one that presents a problem for players at all levels of skill (and that won’t be solved in a few paragraphs in this article!). There are a few key aspects to bear in mind when faced with the choice to open the hand.

The key benefit for opening the hand is that you can progress it towards tenpai by claiming a tile. This is particularly important when calling shapes with low tile acceptance (such as 89, or calling pon on pairs), because the chance of you completing the shape with a tile you draw yourself is relatively low.

This benefit comes with a few drawbacks. The main one is that a lot of yaku decrease in value or aren’t valid at all when the hand is open. When considering our desire to have 3 to 4 han in our hand, losing access to yaku like riichi and pinfu can be quite a large downside, especially when others such as honitsu and sanshoku are decreased by one as well. Achieving a mangan with an open hand is a lot more difficult/unlikely than achieving one with a closed hand.

In addition, calling a tile locks part of your hand into an open meld. This restricts the flexibility of your hand to potentially switch up into a different shape, and it also can severely limit your ability to defend (which we’ll get onto in Article 6). It also reveals information about your hand to your opponents – what yaku you are potentially pursuing, and whether your hand is likely to be cheap or expensive to deal into.

What’s important is to bear this trade-off in mind when playing, and ensure that when you call a tile you are doing it because it’s a good idea, rather than just because you can. The majority of the hands that you play should remain closed, and if you’re calling more than 30-40% of the hands that you play, you are probably calling too often.

As a general rule of thumb, try and keep to 3 han minimum, especially with calls on the first row of discards. Calling early for a tanyao or fanpai hand with two dora is typically a strong move, whilst calling early for a tanyao hand that’s only going to be one han is typically not.

For more info on the pros and cons of calling, and when calling is good or bad, see our translation of Puyo’s Guide to Calling Tiles.

That concludes this article on yaku and value. In the next part, we’ll look at the most important yaku and the name of the game: riichi!