Riichi Mahjong · 2 han（closed only）
Chiitoitsu (Seven Pairs) in Riichi Mahjong: Han, Fu, Waits and Odds
In riichi mahjong, Chiitoitsu (seven pairs) is a closed-only yaku worth 2 han: the winning hand is seven different pairs. Besides kokushi musou, it's the only way to win without four sets and a pair, and its fu is fixed at 25.
On this page
The rules for Chiitoitsu
- Seven pairs, all of different kinds: four of the same tile doesn't count as two pairs (same as Tenhou and Mahjong Soul)
- Closed only: no chi, pon or kan (collecting pairs never needs them anyway)
- Any tile can be a pair: suited, honors, terminals
- Fu is always 25 — no extra fu, tsumo included
How Chiitoitsu waits
A chiitoitsu tenpai is always six pairs and one loose tile, so it's a single wait on that tile. The upside is that you choose the wait yourself:
- Honors: other players can't use them, so they get discarded
- Tiles with one or two copies already discarded: the rest are hard for others to use, so they come out (a wait on the very last copy is called a "hell wait")
- Suji and terminals: tiles other players think are safe
How Chiitoitsu is scored
The yaku, han, fu and points below are computed live by the same scoring code the game uses.
Ron
| Chiitoitsu | 2 han |
| Total | 2 han 25 fu · 1,600 points |
|---|
Non-dealer, East round, no dora, no honba.
Riichi · Tsumo
| Riichi | 1 han |
| Menzen tsumo | 1 han |
| Tanyao | 1 han |
| Chiitoitsu | 2 han |
| Total | 5 han 25 fu · Mangan · 2,000 / 4,000 points |
|---|
Non-dealer, East round, no dora, no honba.
Ron
| Chiitoitsu | 2 han |
| Honitsu | 3 han |
| Total | 5 han 25 fu · Mangan · 8,000 points |
|---|
Non-dealer, East round, no dora, no honba.
Common combinations:
| Combination | Han |
|---|---|
| Chiitoitsu | 2 |
| Chiitoitsu + riichi | 3 |
| Chiitoitsu + riichi + tanyao | 4 |
| Chiitoitsu + honitsu | 5 |
| Chiitoitsu + honroutou | 4 |
| Chiitoitsu + chinitsu | 8 |
At 25 fu, a low-han chiitoitsu is cheap, but stack riichi, tanyao and dora (a dora pair is two dora) and it reaches mangan easily.
How it relates to other yaku
- Ryanpeikou: a shape like 223344 also splits into seven pairs. This game scores both and takes the higher one (usually ryanpeikou).
- Toitoi: the other yaku to think about with many pairs. If you can pon, toitoi; if you want to stay closed, chiitoitsu.
- Honroutou, chinitsu, honitsu, tanyao: they depend only on which tiles you use, so they combine with chiitoitsu.
- Tsuuiisou: seven pairs of the seven honors is also tsuuiisou, a yakuman.
- Yaku that look at sets — pinfu, iipeikou, sanankou — never come with chiitoitsu.
Chiitoitsu odds
How many pairs you start with
A 13-tile starting hand has 4 or more pairs about 2.2% of the time, and 5 or more only 0.11%. You need seven, so starting with four is already a good start.
| Pairs in the starting hand | Chance |
|---|---|
| 1+ pairs | 87% |
| 2+ pairs | 50% |
| 3+ pairs | 15% |
| 4+ pairs | 2.2% |
| 5+ pairs | 0.11% |
Source: 1,000,000 random 13-tile deals.
When the four computers on this site play normally, chiitoitsu is in 3.7% of wins, those wins average 11,500 points, and 44% of them are by tsumo.
Is it worth forcing Chiitoitsu?
We let computers play on this site's table: in every hand, the player with the most pairs had to go for chiitoitsu — no calls, keep pairs and discard loose tiles (when equal, the one with fewer copies left), riichi once tenpai, and no win without chiitoitsu — while the other three played normally. Then we compared the average result with the same starting hands played normally.
| Pairs in the starting hand | Starting hands | Made it | Someone else won | Draw | Avg. points forcing it | Avg. points playing normally |
|---|---|---|---|---|---|---|
| 2 or fewer | 11,319 | 3.8% | 73% | 24% | −1,130 | +90 |
| 3 | 10,143 | 7.3% | 72% | 20% | −650 | +342 |
| 4 | 2,357 | 14% | 66% | 20% | +219 | +847 |
| 5+ pairs | 181 | 29% | 49% | 23% | +2,923 | +3,113 |
Source: computer play on this site. In each of 24,000 hands the seat with the best start forced Chiitoitsu (no calls, riichi once tenpai, no other win); the other three played normally at normal level. Points are the hand’s gain or loss, including riichi sticks.
The result: forcing chiitoitsu loses to normal play in every group. The more pairs you start with, the smaller the gap — from 5 pairs the two are close — but normal play still comes out ahead. The normally playing computers already drift into chiitoitsu when they hold many pairs.
- With 4 or more pairs, forcing it works about 15% of the time, for an average of +412; the same starts played normally average +975.
- With 5 or more, the success rate is 29% and the average +2,923, against +3,113 for normal play.
- Counting starts with just 3 pairs too (3 or more), the success rate drops to 8.8%.
- Finished hands averaged 4.9 han and 11,000 points, after 12.8 discards.
Which hands suit Chiitoitsu
- 4 or more pairs at the start, and sets and partial sets that don't connect well.
- Many pairs you can't pon: tiles already discarded or ones others won't throw — chiitoitsu doesn't depend on anyone else.
- A dora pair: that's two dora on its own, and chiitoitsu makes value easily.
- When you want to keep safe tiles: chiitoitsu has no sets, so a safe tile can stay in hand as a pair candidate — good for balancing attack and defense.
When to give up: the pairs won't come and you're still at four with half the wall gone, or someone declares riichi and you're two or more tiles away. To practice picking waits, open a table of free online riichi mahjong.
Seven pairs in other mahjong styles
- Sichuan mahjong "Seven Pairs": 2 fan (Sichuan mahjong Seven Pairs); four of a kind counts too as "Dragon Seven Pairs", 3 fan (Sichuan mahjong Dragon Seven Pairs)
- Chinese Official (Guobiao) "Seven Pairs": 24 fan (Guobiao fan list)
- American mahjong's pairs hands: no jokers allowed there either (American mahjong Singles & Pairs)
FAQ
How many han and fu is Chiitoitsu?
Chiitoitsu is 2 han with a fixed 25 fu, closed only.
Can four of the same tile be two pairs?
No. As on Tenhou and Mahjong Soul, all seven pairs must be different tiles. Four of a kind is one pair plus two extra tiles.
Can you call for Chiitoitsu?
No. It's a closed-only yaku; after a chi, pon or kan there's no chiitoitsu.
What if chiitoitsu and ryanpeikou both fit?
Only one counts. This game scores both and takes the higher. With 223344 characters, 667788 dots and a 5 bamboo single wait, ryanpeikou plus tanyao beats chiitoitsu plus tanyao, so it's ryanpeikou.
Related yaku
Toitoi Closed 2 / open 2
Four triplets and a pair, still 2 han when open. Examples, scoring combos and how many starting pairs you need.
Ryanpeikou 3 han（closed only）
Two iipeikou, closed only, 3 han. Examples, the difference from chiitoitsu, combos and how rare it is.
Honroutou Closed 2 / open 2
Only 1s, 9s and honors — 2 han even when open, always with toitoi or chiitoitsu. Examples, combos and odds.
Try it at the table
Riichi Mahjong — Play Japanese Riichi Mahjong free in your browser against three AI opponents. Standard online rules with red fives, ippatsu and ura dora, a yaku guide, wait and furiten hints, and three AI levels. No sign-up.