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Mahjong Master
advanced Yakuman Very Rare

Ryuuiisou

緑一色 | Ryuuiisou

Build your entire hand using only the green tiles: 2s, 3s, 4s, 6s, 8s in bamboo and the green dragon (hatsu).

By Kenji Tanaka · Updated

Overview

Ryuuiisou, all green, is an unusual yakuman in which every tile in your hand is green in color, drawn only from the green-printed tiles: the 2, 3, 4, 6, and 8 of bamboo plus the green dragon (hatsu). Some strict rule sets require the green dragon to be present, while others allow the hand from the green bamboo tiles alone. Because its tile pool is so narrow, ryuuiisou is one of the rarest yakuman and almost always relies on a bamboo-heavy start and pon calls. It naturally tends toward honitsu or chinitsu in bamboo and often toward toitoi, and the green dragon can also supply yakuhai along the way. The defining feature is purely visual, the green coloring of the tiles, which makes it a distinctive and memorable hand. As with other yakuman, opponents fold quickly once a suspicious cluster of green bamboo and dragons appears on the table.

Han Value
Yakuman

Example Hand

222s 333s 666s 888s 6z 6z

Conditions

  • Every tile in the hand must be one of the “green” tiles: 2s, 3s, 4s, 6s, 8s (bamboo) and/or 6z (hatsu/green dragon)
  • No other tiles are allowed — not even other bamboo tiles like 1s, 5s, 7s, or 9s
  • The hand can be open — calling pon or chi on green tiles is allowed
  • The only possible sequence is 2-3-4 of bamboo; all other melds must be triplets
  • Hatsu (green dragon) is not required in all rulesets, but some rulesets do require at least one hatsu tile to be present

Strategy Tips

  • Ryuuiisou is named “all green” because the qualifying tiles are depicted with only green ink on traditional bamboo tiles. The valid tiles are a quirky set to memorize: 2, 3, 4, 6, 8 of bamboo plus hatsu.
  • The 2-3-4 bamboo sequence is the only possible sequence in ryuuiisou, which severely limits your hand structure. Most ryuuiisou hands rely heavily on triplets of 2s, 3s, 4s, 6s, 8s, and hatsu.
  • If your starting hand has several green bamboo tiles plus hatsu, keep ryuuiisou in mind as a long-shot possibility. Even if you don’t achieve the yakuman, you may be building toward honitsu or chinitsu with bamboo tiles, which gives you a fallback plan.