Curriculum · 30 / 50
Suji: the 1-4-7 lines
Suji cuts your risk when safe tiles run out: a discarded tile makes its 1-4-7, 2-5-8 and 3-6-9 lines safer against a ryanmen wait, not a certainty.
The principle
Suji (筋) refers to the tile lines linked by ryanmen waits, which always accept two tiles spaced three ranks apart. Within each suit (man, pin, sou) this creates three lines: 1-4-7, 2-5-8 and 3-6-9. Reading these lines lets you guess which tiles an opponent cannot be waiting on with a ryanmen.
Rule and example
The idea rests on furiten. If an opponent discarded 4, they cannot ron 1 through a 2-3 wait or 7 through a 5-6 wait, because both ryanmen also wait on 4. The 1 and 7 are therefore suji against those ryanmen only. To cover both possible ryanmen for 5, both 2 and 8 must have been discarded.
What changes
The crucial limit: suji only protects against ryanmen waits. It says nothing about a kanchan (3-5 waits on 4), a penchan (8-9 waits on 7), a shanpon (pair wait) or a tanki (single-tile wait). A suji tile is therefore a bet, not a guarantee like genbutsu.
Mistake to avoid
In practice you play suji once the genbutsu against the threat's ron run out: it lowers part of the risk, but does not remove it. Watch for suji traps where an opponent keeps a kanchan or shanpon on a tempting suji tile. Keep counting tiles and reading the kawa instead of trusting the line blindly.
Rules references
- Tenhou rulesReference profile used for game mechanics and scoring.
- WRC Rules 2025International rules compared whenever their options differ from Tenhou.