Tina's Tactics 2: Defense And Knowing Your Kikenhai – Reading Suji From A Different Angle

Last post I shared some tips on reading suji and received a surprising amount of positive feedback. Thank you to those that took time to read it, and I’m happy to know that these tips are helping your gameplay.

I am back to share some additional information. I got feedback that I should cover techniques that have not yet been discussed in the limited resources already available in English, so I am going through them to figure out what information would be fresh and new. However, I expect this to take time, so please be patient. If there are any topics that you feel needs more coverage, I would appreciate suggestions.

Meanwhile, I will dive further into the topic of suji. If you remember the last posting, the suji number groupings were 1-4-7, 2-5-8, and 3-6-9. By reading Omote-suji (Front Suji) and Naka-Suji (Center Suji), you now know how to look for anpais. However, it is all too common that your hands do not have any anpais, or you have a good hand and you do not want to fold. Out of the many not-safe-tiles (which are essentially everything other than anpais) it is important to know which tiles are more likely to be the other player’s winning tile. If the tile that you wish to discard is highly likely to be the winning tile, you may want to reconsider the option to fold.


Today I am sharing some additional ways to utilize suji to find kikenhais 危険牌– Danger tiles. Note that this skill again assumes that the other player has a two-sided wait (ryanmen) This technique is useful and worth studying, but it is a theoretical concept and should not be heavily relied on in your playing.

Ura-suji: translates to “Back Suji”. When a player discards a number tile, the neighboring number and its suji is dangerous. For example, if a player discards a 1p, the 2p (following number) and 5p (suji of 2p in the 2-5-8 grouping) are dangerous. How do we know? Let’s look at the tiles from the player’s perspective. If you had a 1p-3p (kanchan wait), then drew a 4p, you would discard the 1p and hold a 3p-4p for a better wait. Now you have a two-sided wait on 2p and 5p, the ura-suji of the discarded 1p.

This pattern applies all across the number tiles, but discards higher than 5 should look at the lower neighbor. If the discard was a 8m, the 7m (next of discard) and 4m (suji of 7m in the 1-4-7 grouping) are dangerous. From the player’s point-of-view, if you had a 6m-8m, then drew a 5m, you would discard 8m and change this into a two-sided wait. As a result you have 5m-6m and the winning tiles are 4m and 7m.

Discard ura-suji:

1    2 & 5

2    3 & 6

3    4 & 7

4    5 & 8

5    1, 4, 6, & 9

6    2 & 5

7    3 & 6

8    4 & 7

9    5 & 8

These skills are most applicable towards the tiles discarded on or a few turns before riichi (or dama tempai if you can tell!), because the players are more likely to start organizing the tile groups into a preferred two-sided wait as they get closer to tempai.


For several reasons, I find it alarming when a person discards a 5. First, it has the most kikenhais: 1, 4, 6, 9. Why so many? Because the discarded 5 does not give away whether the player is holding the lower numbers or higher numbers. For example, the player may have had 3-5, then drew a 2. He discards 5, resulting in a 2-3 two-sided wait for a 1 or 4. He also could have had a 5-7, then drew a 8. He discards 5, resulting in 7-8 two-sided wait for a 6 or 9. This is virtually impossible to tell, and I will need to look for more hints.

Second, WHEN the 5 is discarded will provide different information. Generally, the center tile 5 connects easily with others and is a tile that most people hold on to in the beginning. If the 5 is discarded in the beginning, there is a high chance that the player is or is close to tempai, and the 2-3 or 7-8 wait is ready in place. Given the possibility of chanta and an extra han, the 1 or 9 tile will need to be handled with care.

On the other hand, if the 5 is discarded in the middle or towards the end of the game, there is a high chance that the matagi-suji 3-6 and 4-7 are dangerous. As discussed above, people are more likely to hold longer on to a 5. Thus, it is common for the hand to develop into the shape of 455 or 556. Then later, at tempai, the 5 is discarded for a 4-5 or 5-6 two-sided wait. Matagi-suji is a topic I haven’t covered, but is available for reading at David Clarke's Osamuko.

Speaking of discarded 5’s, during a recent game review with LAPOM Riichi Mahjong Group らぽん, Nima referred to a video of Kosho Tsuchida Pro that discusses what to watch out for when another player discards a 5 and declares riichi on the 8th or 9th turn. The video can be viewed at: https://youtu.be/XjpYNDy_Ds4. Since the video does not allow users to add comments or subtitles, I have summarized Tsuchida Pro’s points.

Happy Riichi!

Houston-based Japanese-American riichi player Tina Koshimoto shares her knowledge in our Mahjong News series "Tina's Tactics". This article premiered on 'Dallas/Fort Worth Mahjong'. Mahjong News' publication includes the author's translation of the YouTube video.

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Comments (1)

  • Hey! I really like your articles, Tina! About Tsuchida-san's video translation- what a great idea! Thank you so much for that! Is there any chance for that to become a series? I'm sure many Western players wonder about Tsuchida-san's theories because he's such a charismatic and well known player.

    You probably know about that website already :)

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