Tina's Tactics 1: Defense and Knowing Your “Anpai” – Understanding Suji

There is a vast amount of riichi tips published in strategy books and mahjong websites, but I know that a majority of these resources are in Japanese and are not accessible for most of you. I thought it would be a fun idea to share some of these tips, since I know how frustrating it is for those wanting to improve. I will try to share tips that I personally thought were helpful in my training. Please feel free to comment if you have any specific topics or questions that you’d like me to address. I referred to the WRC book for the technical terms, but I learned riichi in its original language so I apologize in advance on the parts that I do not use accurate English terms.


When another players declares riichi, I will often scramble through my tiles to find an anpai in order to avoid dealing in to that player. An “Anpai 安牌” translates to “Safety Tiles”, meaning that it is a tile with little or no chance that the other players will declare a win on it. The safest anpai is of course what a player has already discarded, because the furiten rule does not allow a player to call ron from another player on a tile that they already discarded. However, what do you do when you run out of these anpais? Then, you need to read the discarded tiles and determine the tiles that are at least less likely to be that player’s winning tile.

Reading suji

One way to do this is by reading suji. This is a useful tool when a player is tempai and has a chow with a two-sided wait (ryanmen wait); Example: 2-3, winning tiles 1 or 4. The basic concept of suji revolves around 3 sets of number groups: 1-4-7; 2-5-8; and 3-6-9. Let’s go through some examples to determine how a suji works!

Omote-suji: translates to “front suji.” When a player has discarded the center number in the number group, the outside numbers are relatively safe. Let’s look at the 1-4-7 number group to better understand this idea. The center number in this group is 4. If a player discards 4s, this will mean that 1s and 7s is less likely to be that player’s winning tile. Why is that? Because if the winning tile is 1s, that means that the player had a 2s 3s in his hand. This is a two-sided wait (1s and 4s), so declaring ron on a 1s while discarding a 4s would be a furiten. Same with 7s; if the player’s winning tile is a 7s, this means that the player had a 5s 6s. Declaring ron on a 7s while discarding a 4s would be a furiten. This will not work of course if the player originally had 4s 8s 9s, and discarded 4s to wait on 7s, a penchan wait. The suji technique only applies to two-sided waits.

Naka-suji: translates to “center suji.” When a player discards the outer two number in the number group, the center number is relatively safe. Now let’s look at the 3-6-9 group. If a player discards a 3m, does that mean 6m is safe? If that the player has 4m and 5m, yes, because declaring ron on a 6m while discarding a 3m would be furiten. BUT WAIT! What if the player had a two-sided wait with 7m and 8m? You’ve just dealt into the other player, say goodbye to your points.

This is where the naka-suji is useful. What if the player had discarded 3m AND 9m? Then, the chances are that he is unlikely to be waiting with a 4m-5m or a 7m-8m chow. Ultimately, 6m becomes a relatively safer tile in this situation.

Discards of multiple players

Naka-suji reading can be used also by looking at discards of multiple players at the same time. For example, you are in East and the South player (right of you) calls riichi and discards 2s. You immediately think of the 2-5-8 number group. However, as mentioned in the example above, this could possibly mean that 5s is safe, but you don’t know because he might be waiting with a 6s 7s. Then, the West player (across from you) discards 8s. What a courageous move! The South player does not declare ron, and the 8s has now become anpai. By combining the fact the 2s and 8s are both anpais, you can now determine that the 5s is relatively safe, at least against the South player’s tempai.

Allow me to emphasize that reading suji only works with two-sided waits, but not tanki, shabo, kanchan, or penchan waits discussed above. To illustrate shabo in the last hypothetical, the South player who declared riichi could have ②③④ 123 55 777 北北. Winning tiles are 5 and 北. The 2s discarded upon riichi and the 8s discarded by the West player (or even by the South player himself) will not give you any hints on this hand’s wait. Some advanced players will use this as a trap to pull out the winning tile from you, so be aware!

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'. Photo credit: Chuck Ford.


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