Tips for Scoring Riichi Mahjong Hands in Real Play

Written by Riichi Nomi member and Captain of the Honba Hunters Josh Kwan

Even the most ardent fan of Riichi Mahjong will confess to you that it's a game with a steep learning curve. The steepest part of the curve is no doubt the process of hand scoring during in-person play. Not only is this something you need to do at the end of a hand that you've won, but ideally you should be doing it as you build your hand, so you know how much it's worth pushing your hand versus folding.

There are enough articles out there about how scoring works. To read comprehensive explanations, check out these pages: Japanese mahjong scoring rules - Wikipedia ; MJ Stars ; and Light Grunty's videos 1, 2 and 3. This article is designed for people who have a general idea of what to do, but feel a cold sweat right after they call Ron or Tsumo as they realize they are responsible for taking care of the scoring (or have to let a friend do it for them.)

Here, I'll be giving my top tips as someone who's recently been a beginner, and can get you to 80~% accuracy in real games within just a few seconds.

Tip 1: Know the yaku inside and out, and in order

This sounds obvious, but you just have to memorize the yaku table first and foremost. Most players start out by using a crib sheet like Chase's excellent one.

One thing that you will find with experience is that certain yakus tend to go together. For example, yakuhai (dragon / own wind) pons tend to pair up with Hon Itsu (half flush) hands, pinfu often occurs with iipeikou (Pure Double Chow) or sanshoku (Three Color Straight), and of course, we can't forget the combination of riichi ippatsu tsumo making a self drawn riichi win worth 3 han at a minimum!

By memorizing not only the yakus but how they relate to each other and cluster together, you can have an easier time.

Here are some 'groupings' of yaku that I like to think of:

• Regular circumstances: Riichi, Ippatsu, Tsumo, Dora and Ura-dora

• Sequence based: Pinfu, Iipeikou, Ittsu, Sanshoku doujun

• Triplet based: Toitoi, San An Kou, Sankantsu, Sanshoku doukou, Honroutou, Chinroutou, Suuankou, Suuankou Tanki and Suukantsu

• Flush based: Hon Itsu, Chin Itsu, Chuuren Poutou

• Weird Stuff: Chiitoi, Kokushi Musou, Nagashi Mangan

• Insane circumstances: Tenhou, Chiihou, Haitei, Houtei, Chankan and Rinshan Kaihou

If you remember the groupings, you may well recall which of the groupings occur in your hand, then drill down into which of the specific ones apply to get a precise han calculation.

Finally, it is conventional to mention the yaku in your hand in a specific order. This can help you establish muscle memory for hands of a certain type. The order goes, roughly:

• Circumstantial (except Dora): Riichi, Ippatsu, Tsumo, Haitei, Houtei, Chankan

• Those which conclusively define fu values: Pinfu or Chiitoi

• Everything else except Dora

• Count of Regular Dora

• Count of Ura-dora (if applicable)

Examples:

• Riichi Pinfu Dora 1 Ura 2

• Riichi Ippatsu Tsumo Tanyao Ura 1

• Chiitoi Dora 2

  
  

Tip 2: Understand how the scoring table is made

When people see a classic scoring table like this for the first time, it might as well be in hieroglyphics!

Seemingly random numbers are placed next to each other. Memorizing it seems like an enormous mountain to climb. But, instead of trying to memorize every cell of the table by rote, understanding the basic principles which generate the table may be more fruitful.

To quickly recap the scoring principles, every hand has two scoring components, Han and Fu. Han is "easy", in that they are sums of yaku worth as few as 1 and as many as 6. Just count up all the yaku you have and you get your Han value. Don't forget to add Dora to the final total.

Fu is where people tend to glaze over! Generally, fu are calculated from a base starting score, and adding small numbers like 2 and 4 for very basic aspects of your hand composition, such as the number of triplets you have, whether they are opened or closed, and the nature of your final wait. Then, round up to the nearest 10. The key takeaway here is that the rounding aspect often makes it much easier to guesstimate a hand's fu value and be correct.

For the mathematically inclined, when a hand is worth less than Mangan, Han and Fu relate to each other like this:

Total Hand Value = (Fu + Constant) 𝖷 2^{Han + Constant} , round to nearest 100

The constants don't matter for our discussion, though you can read about that here. The key takeaway here is that Fu determines a base hand value, and each Han will double that base value as many times over as there are Han (until limit hands are reached.) This means that we can memorize base hand values, and then simply double them according to the number of Han.

Let's get into it!

2A: Non Dealer Scoring

Now that we understand the formula, let's look at the evolution of hand values for various Fu, as Non-Dealer, scored with Ron. If you only memorize these, you will be good for 70-80% of all hands played.

• 25 fu (starting from 2 Han): 1600 → 3200 → 6400 → Mangan (8000)

• 30 fu: 1000 → 2000 → 3900 → 7700 → Mangan (8000)

• 40 fu: 1300 → 2600 → 5200 → Mangan (8000)

• Mangan 8000 → Haneman 12000 → Baiman 16000 → Sanbaiman 24000 → Yakuman 32000

You might be familiar seeing these values from playing online games where your score is calculated. These final hand values occur extremely often. If you just memorize the base values of 1600, 1000 and 1300, then double accordingly, you don't need to memorize every single number.

There are, of course, exceptions. For example, the 3 han and 30 fu score of 3900, and 4 han 30 fu score of 7700, look like they should be 4000 and 8000 respectively. This is an artifact of rounding and it helps to simply memorize these as exceptions to the rule. Additionally, some tournament rules do round up 7700 to 8000, acknowledging the lack of value for the complexity. This rule is known as Kiriage Mangan, and Riichi Nomi uses it in our Classic ruleset and at the Riichi Nomi Open.

2B: Dealer Scoring – worth 1.5x more!

Finally feeling confident about the non-dealer ron scoring table above? Your heart may sink when you realize the numbers seem to look totally different for dealers!

But don't worry, the easy way to remember it is that any hand is worth 1.5 times more. In the case of mangan and haneman, that means 8000 and 12000 for non-dealers becomes 12000 and 16000. In the cheaper cases, we'll reproduce the Ron table from above but now as the Dealer. Base values are bolded.

• 25 fu (starting from 2 Han): 2400 → 4800 → 9600 → Mangan (12000)

• 30 fu: 1500 → 2900 → 5800 → 11600 → Mangan (12000)

• 40 fu: 2000 → 3900 → 7700 → Mangan (12000)

• Mangan 12000 → Haneman 18000 → Baiman 24000 → Sanbaiman 36000 → Yakuman 48000

Indeed, if you do the math you will see that the numbers are indeed roughly 1.5x the non-dealer numbers.

Perhaps the trickiest line is 30 fu. Going by doubling, it should be 1500, 3000, 6000 and 12000. Instead, we are 100 short at each time and the doubling keeps making the gap worse. One way to remember it is to remember 1450 as the base value for 30 fu dealer, but that 1450 has to be rounded up since there are no 50 point sticks. From there, regular doubling takes place. Next, a great way to remember the 40 fu line is that it's the same as 30 fu non-dealer, but with 1 extra han. This works because of the associative property of multiplication: (x*2)*2^y = x*2^(y+1).

2C: Know what to do for Tsumos

Now that we know what to do for Ron, we can use that information to help us with Tsumo. First, keep the non-dealer Ron values above in mind. Then,

If you are not the dealer: The dealer pays half and the other two pay a quarter of your hand value. (8000 Mangan = 2000(Non Dealer) : 4000(Dealer)

If you are the dealer: All other players pay a third of your hand value. (12000 Mangan = 4000 All)

As we've continued to see, the only gotchas are unclean division and rounding. For example:

• 3 Han 30 Fu Non Dealer Tsumo is worth 3900 points, but paid as 2000(Dealer) : 1000(Non-Dealer) for a total of 4000 points.

• 1 Han 30 Fu Non Dealer Tsumo is worth 1000 points but paid as 500(Dealer) : 300(Non-Dealer) for a total of 1100 points.

• 2 Han 30 Fu Dealer Tsumo is worth 2900 points but paid as 1000 All for a total of 3000 points.

If you play online, you will see these values come through in games, and I believe it will be easy to recall the exception values if you remember the principle behind the allocations.

Tip 3: Have a plan and stick to it

You probably have heard about and read about all the things you need to do to score a hand, not only in this article but in many others. If you have some familiarity with all the steps, you just need to practice until each step becomes second nature. Not all the steps will click at once. Don't be discouraged and just stick to your plan and it will begin to come naturally!

It can help to look at a flow chart that lays out the steps you'll need to take. Here's one that represents my mental model. Depending on how your brain works, you might want to structure it differently. This is how my brain works and I'm sure everyone's is different!

• Am I the dealer? → Choose between dealer and non dealer scoring

• How much is the hand worth?

  • How much han is it worth?

    • Is it 4 or more? → Mangan, Haneman etc.

    • Is it fewer? Count fu, below

  • How much fu is it worth?

    • Is it Closed-Ron? → 30 Fu if Pinfu, 40 Fu and above otherwise

    • Is it Pinfu-Tsumo? → 20 Fu

    • Otherwise 20 Fu and above (but probably 30 or 40 most of the time!)

  • Final calculation of hand value using base value tricks above

• How will it be paid? → Tsumo vs Ron

• Are there repeats? → Add repeat value to the final score. Normal scoring is 300 per repeat on Ron, 100 for each person on Tsumo.

  
  

Put it all together: Announce

Adapting Japanese etiquette around announcing your winning hand to English, here are a couple ways to wrap up all of your score calculations and announce your hand value to people in a clear, comprehensible fashion. These steps should be followed in order.

• Say Ron or Tsumo and reveal your hand.

• If you scored a limit hand, announce which limit you hit (mangan, haneman etc.) (*)

• If you tsumo,

  • And you're the dealer, say the score that everyone must pay, such as '4000 all'.

  • And you're not the dealer, say the score that nondealers must pay, followed by the dealer's payment, such as '2000-4000'.

• If you ron, say the score that the person who gave you the winning tile must pay.

• If there are honba adjustments, announce the payments again, with adjustments. You can connect the two announcements with 'is' or 'becomes'. Such as '2000-4000 is 2600-4600' or '4000 all becomes 4200 all'.

  • Alternatively, you can announce the number of honba only. '2000-4000 2 honba'; while this seems to be current in some Japanese parlors, it is not recommended due to possible ambiguity.

Note that you are not expected to announce fu, but the announcement will imply a certain fu value. As a player auditing a score announcement, you should figure out the fu that the winner implied, and make sure the hand does have those fu before making your payment.

Bonus: Abbreviations

If you have watched Japanese people play mahjong in settings where they announce their yaku, you might notice some abbreviations that are surprising.

• "Pin" for Pinfu

• "Tan" for Tanyao

• "Soku" for ippatsu (即)

• "Men" for Menzen which is used for two purposes:

  • Used with 'pin' to indicate a 'riichi pinfu': e.g. menpin dora 1

  • Used with kuisagari (calling decrease) yakus, such as honitsu and chinitsu, to indicate the uncalled variety worth 1 han more: menchin and menhon

  • Though oddly enough, never mentioned in conjunction with sanshoku or chanta / junchan

• Men, Tan and Pin abbreviations, in any combination, would always be used in this order. so Mentan, menpin, tanpin but never pintan or tanmen.