Ittsu (一気通貫)
2 han
1-2-3 + 4-5-6 + 7-8-9 chows all in the same suit.
Example winning hand
Winning tile: 5s
How Ittsu (一気通貫) works
A straight 1-through-9 in a single suit, formed as three runs: 1-2-3, 4-5-6, and 7-8-9 all of the same suit.
Ittsu, the pure straight, is completed when one suit supplies the full ladder of three consecutive sequences, leaving the fourth set and pair unrestricted. It can be made with an open hand, though calling a chow reduces its value. It commonly combines with the flushes, since all three runs sit in one suit anyway.
Good to know
- •All three runs must be in the same suit; spanning suits does not qualify.
- •Both open and closed hands can score it, with the open hand worth one less.
- •It stacks well with honitsu and chinitsu given its single-suit structure.
Ittsu (一気通貫) — FAQ
Can the 1-9 straight span two suits?
No. The three sequences must all belong to one suit; mixing suits breaks the pure straight entirely.
Does calling a chow lower ittsu's value?
Yes. Like many sequence yaku, an open ittsu is reduced by one han compared to the concealed version.
Other 2-han yaku