Suji… The first defence tool in a Riichi mahjong player’s tool box. But just relying on suji alone can be a bit of a blunt tool. Suji is more like reading the tea leaves and you need to be careful of their placement in a discard pile.
What is suji? I didn’t write THAT article yet, but I’m going to presume you already know. If you don’t, osamuko.com or mahjong.guide will help!
I have two suji warnings for you…
(1) Never trust the outside suji unless you can see both on the same suji string. It’s like flags at the beach, you need to make sure you’re within both flags. If you only see one flag, think DANGER OF DROWNING (in someone else’s points total)!
So if you see just a 9, neither the 6 or the 3 are safe. However, if you see a 9 and a 3, the 6 is very likely to be safe. These are known as “naka-suji” or inside suji.
(2) The riichi call tile is never safe for suji reads. NEVER! We can’t assume that our opponents are always making double sided waits. Check out the below…
You throw the 5p for a wait on the 2p alone. It’s not uncommon!
I also heavily disagree with anyone who says this is a suji trap. It’s not a trap because no one should be falling for this one. If you throw the 5 earlier than the Riichi, sure, call it a suji trap. But that Riichi declaration tile should always be considered a dangerous indicator of what is in an opponent’s hand. TREAT WITH CARE!
(Reference material: Takunori Kajimoto, Perfect Defence Manual pp.42-43)