Ryuuiisou (緑一色)
13 han
All-green — only 2,3,4,6,8s and 6z.
Example winning hand
Winning tile: 6s
How Ryuuiisou (緑一色) works
Ryuuiisou (all green) is a yakuman using only tiles that are entirely green: the 2, 3, 4, 6, and 8 of bamboo plus the green dragon (hatsu).
Every tile in the hand must come from that restricted green set, so the hand is built only from those bamboo tiles and green dragons. It works open or closed. Because all permitted tiles are bamboo or the green dragon, it inherently overlaps with honitsu and, in many of its forms, chinitsu-adjacent bamboo shapes.
Good to know
- •Only 2s, 3s, 4s, 6s, 8s and the green dragon (hatsu) are allowed.
- •Some rules require the green dragon to be present; others accept an all-bamboo green hand without it.
- •The 1, 5, 7, and 9 of bamboo are excluded because they contain non-green markings.
Ryuuiisou (緑一色) — FAQ
Why is the 5 of bamboo not allowed?
The 5 of bamboo contains red, so it breaks the all-green requirement. Only 2, 3, 4, 6, 8 bamboo and the green dragon are purely green.
Is the green dragon required for ryuuiisou?
It depends on the ruleset. Some require hatsu to be in the hand, while others allow a fully green bamboo-only hand to qualify.
Other 13-han yaku