Pure straight 一気通貫 · ittsuu (ikkitsuukan)
The sequences 1-2-3, 4-5-6, and 7-8-9 in one suit — a straight through the whole suit.
| Value | 2 han closed · 1 han open |
|---|---|
| How often | common |
Ittsu shows up when one suit dominates your draws and its tiles spread across the whole range instead of clustering. Hold 12356789p and you are one tile, the 4p, from the full straight. The check that matters: the blocks must sit exactly at 123, 456, and 789, so read your long suit in those frames before you commit to it.
The near-miss is the classic trap. A stretch like 2-3-4-5-6-7 looks close but counts as two ordinary sequences, not as straight blocks, and no single draw repairs it cheaply. The tile that rescues an ittsu hand is often a terminal, the 1 or 9 you were tempted to discard early, so when one suit runs long in your hand, hold its end tiles a few extra turns.
Open, ittsu keeps a yaku but drops to 1 han, which matters mostly as a component: an open straight inside a one-suit hand stacks with honitsu, and if the honors fall away the same shape flows toward chinitsu. Closed, declare riichi and treat the straight as the hand's backbone rather than the whole plan.
Key points
- The three sequences must be exactly 123 / 456 / 789 in the same suit — 234, 567 do not count
- 2 han closed, 1 han open
- Natural stepping stone toward honitsu or chinitsu when your hand leans into one suit
Related yaku
- Full flush 清一色 — The entire hand is one suit — the highest-value regular yaku in the game.
- Half flush 混一色 — The whole hand uses a single suit plus honor tiles.
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