How to play Dragon tiles effectively in Japanese mahjong

An advanced riichi mahjong strategy guide series

Kuan Rong Chan, Ph.D.
Mahjong Academy
4 min readOct 30, 2021

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Mahjong is one of my favourite hobbies this year. There are different variants of mahjong, but I prefer Japanese mahjong the most. Unlike other variants which focuses more on attack strategies, Japanese mahjong requires mastery of both attack and defensive strategies. The most convenient platform to play this game (especially during this COVID-19 pandemic) is Mahjong Soul (nickname: kuanrongchan, ID: 118740846), of which I have attained the Master I rank and was in position 6 in one of the tournaments hosted by Mahjong Soul earlier this year.

There are multiple basic guides online, and my personal favourite is the Riichi Book I written by Daina Chiba. However, there are relatively few books that discuss on deep strategies in mahjong. My intent of some of these fun blog posts is thus to discuss some of the deep strategies involved in richii mahjong. In this blog entry, we will specifically discuss on Dragon tiles.

The first thing that comes in most people’s minds will be these high value combinations:

Big Three Dragons yield a Yakuman and Little Three Dragons yield at least 2 Han.

In reality, these situations are very rare, so we should only aim for these combinations if the opening hand contains majority of these Dragon tiles. However, in a typical game, when should we keep or discard Dragon tiles? Before delving in, let’s discuss what are the benefits of keeping Dragon tiles.

The cool aspect of Dragon tiles is that having 3 of them in a set yields 1 Han and satisfies the minimum requirement to win a hand. Dragon tiles are therefore highly efficient especially if you have a pair of the same Dragon tile in your hand, as you can easily “pon” from any player including yourself. This also means that if you have a few red fives or Dora tiles in your hand, having a set of Dragon tiles can accelerate and improve the chances of winning a high value hand. If you are the dealer (1.5x points) or aiming to end a game fast, keeping Dragon tiles can also be useful to quickly assemble a winning hand.

Another scenario where Dragon tiles are useful is when you are forming a triplet hand or half flush, since they are not part of any suit. Both triplet and half flush are at least 2 Han, so having Dragon sets further improves the value these hands, which often brings the hand closer to Mangan.

All the above scenarios may seem to suggest that Dragon tiles are worth keeping. However, in most situations, you want to discard a Dragon tile if you have only one copy. The reason is because there are only 4 copies of each Dragon tile type in the entire mahjong set, which means that the probability of drawing a second Dragon tile to form a pair is low (even lower chance if other players discarded the tiles). Moreover, it has only a small value of 1 Han if you are not forming triplets or half flush, so waiting to form at least a pair of them is usually not worth the effort. To escalate matters, keeping the single tile can be risky in the later stages of the game, as this may mean that another player could be waiting to win on that tile. Hence, based on these reasonings, most players will discard the Dragon tiles early when they have only one copy in their hand.

In summary, prioritise keeping Dragon tiles when:

  1. You already have a pair of Dragon tiles in the starting hand
  2. Dragon tiles are also Dora tiles
  3. You have a potential high value hand with red fives and Dora tiles
  4. You are the dealer (since you have 1.5x points if you win)
  5. Aiming to form triplets, half flush and Little/Big Three Dragons
  6. Aiming to finish games fast (to pressure and secure first or second position in South games)
  7. Keeping as potential safe tiles to discard at late game (If they are in discard pile)
  8. Nobody has discarded the Dragon tile at late game (high chance that someone is waiting for the tile)

Discard Dragon tiles when:

  1. You still have only one copy of the Dragon tile after 5–10 rounds
  2. You have other more efficient or useful tiles (eg middle tiles, Dora tiles or red five tiles)
  3. Other players have discarded the Dragon tiles
  4. You need a bigger winning hand, but do not have a half flush and triplets hand

So that’s it for my take on Dragon tiles and hope you like the article. This article is written with feedback from Kuan Chuan Chan. Stay tuned for more mahjong strategy articles!

Kuan Rong Chan

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Kuan Rong Chan, Ph.D.
Mahjong Academy

Kuan Rong Chan, PhD, Senior Principal Research Scientist in Duke-NUS Medical School. Virologist | Data Scientist | Loves mahjong | Website: kuanrongchan.com