Curriculum · 12 / 50
Sequence yaku: iipeikou, sanshoku, ittsuu, and ryanpeikou
Recognize the four major sequence yaku in riichi, their closed and open values, and the patterns worth preserving.
The principle
Iipeikou is worth 1 han and requires a closed hand. It appears when two runs contain exactly the same numbers in the same suit. Two 3-4-5 runs in circles qualify, while identical numbers in different suits do not.
Rule and example
Sanshoku doujun combines the same run in all three suits. Ittsuu combines 1-2-3, 4-5-6, and 7-8-9 in one suit. Both are worth 2 han closed and 1 han open.
What changes
Ryanpeikou requires four runs that form two independent pairs of identical runs. This closed yaku is worth 3 han, replaces iipeikou, and does not combine with chiitoitsu.
Mistake to avoid
These patterns are value plans, not obligations. Before breaking a block, check the available sanshoku or ittsuu, then compare that gain with the ukeire you would lose.
Rules references
- Tenhou rulesReference profile used for game mechanics and scoring.
- WRC Rules 2025International rules compared whenever their options differ from Tenhou.