is a , open or closed. Every tile is green: the 2, 3, 4, 6, and 8 of sou, and the .
The name players use is ryuuiisou (緑一色). This site's glossary also lists it as All Green, and the EMA 2016 rules use the same English name.
Six green tiles
The whole list is six kinds: 
. The 1, 5, 7, and 9 of sou are out, and so is every man and pin tile.
Only one run uses green tiles alone: 234 sou. Every other set is a triplet or a quad. can't be all green, because six kinds can't make seven different pairs.
The glossary entry is the short form: 2, 3, 4, 6, and 8 sou and the green dragon only.
The winning tile has to be green
You called on green dragon and on 8 sou: and . These seven tiles are still in your hand.
The hand waits on or 
, a .
makes 234 sou. Every tile is green, so that's ryuuiisou. A collects 32,000. The dealer collects 48,000. Fu don't count once a hand reaches the limit.
makes 345 sou, and the 5 isn't green. The hand drops to the green dragon yakuhai, 1 , and honitsu with calls, 2 han. The fu are the base 20, plus 4 for the open dragon triplet, plus 2 for the open 8 sou triplet, plus 4 for the closed 6 sou triplet. That's 30 exactly. At 3 han 30 fu, a non-dealer ron collects 3,900. The dealer collects 5,800.
Those payments have no , no , and no sticks. The scoring guide lists every triplet's fu.
No green dragon needed
No calls and no dragon. Triplets of 2, 3, and 4 sou, and pairs of 6 and 8 sou. The hand waits on or , and both are green.
Tenhou's rules say all green stands without the green dragon. Mahjong Soul's in-game yaku list says the same: "Green Dragon is not Necessary." Either tile is ryuuiisou on both. A ron pays 32,000, or 48,000 to the dealer.
Draw the tile yourself and all four triplets are concealed. That adds suuankou, and both platforms stack yakuman, so the tsumo is a double. A non-dealer collects 16,000 from each other non-dealer and 32,000 from the dealer, 64,000 in all.
The EMA 2016 rules define all green as a hand made entirely of green tiles, and they list the green dragon as one of six green tiles. They don't stack yakuman, so the tsumo pays one there. The World Riichi Championship rules say outright that the hand doesn't need the green dragon.
Open or closed
Mahjong Soul's in-game yaku list marks , , and as closed only, and leaves all green unmarked. The EMA 2016 entry has no concealed condition either. That's the row on this site: yakuman, open or closed.
What sits with it
Every all-green hand is a sou flush, chinitsu without the dragon or with it. Neither adds anything to a yakuman. Suuankou does stack on Tenhou and Mahjong Soul, as the second hand shows. The yakuman page covers how the limit stacks.
Common mistakes
- Counting a 5 or a 7 of sou as green. Only 2, 3, 4, 6, and 8 are.
- Forgetting the winning tile. A 5 sou finish, as in the first hand, ends the yakuman.
- Giving up for lack of a green dragon. Tenhou, Mahjong Soul, and the WRC rules don't ask for one.
- Chasing seven pairs. Six green kinds can't make seven different pairs.
Price an all-green hand
The score calculator pays one yakuman at 32,000 or 48,000 on a ron, and two at 64,000 or 96,000. The 5 sou miss is 3 han 30 fu: 3,900.
Open the score calculator