What is Suu Kan Tsu?
Suu Kan Tsu (Four Quads) is a yakuman (limit hand) in mahjong that requires completing four kan (quads) plus one pair. It doesn’t matter whether the kans are concealed (ankan) or open (minkan/daiminkan) - you simply need four sets of four identical tiles.
With an occurrence rate of approximately 0.00011%, it’s the rarest yakuman in mahjong. Even professional players may never see one in their entire career.
Requirements
| Condition | Details | Notes |
|---|---|---|
| 4 Kans | Any combination of ankan/minkan | Total of 4 |
| 1 Pair | Regular pair for the head | Required |
| Avoid Suu Kan Nagare | Others must not complete a 4th kan | Critical |
Types of Kan Allowed
| Kan Type | Description | Valid for Suu Kan Tsu |
|---|---|---|
| Ankan | Concealed kan from hand | Yes |
| Daiminkan | Open kan from discard | Yes |
| Shouminkan | Added kan to a pon | Yes |
Example Hand
Kans: East×4, South×4, White×4, 1-man×4
Pair: Red Dragon×2The Suu Kan Nagare Problem
The biggest obstacle to completing Suu Kan Tsu is the Suu Kan Nagare (Four Kan Draw) rule:
| Situation | Result |
|---|---|
| One player makes 4 kans | Suu Kan Tsu is valid |
| Two or more players make 4 kans total | Abortive draw |
This means if another player makes a kan while you have 3 kans, the round ends in a draw.
Rarity Comparison
| Yakuman | Approximate Rate |
|---|---|
| Suu Kan Tsu | 0.00011% (rarest) |
| Junsei Chuurenpoutou | 0.000002% |
| Tenhou | 0.0003% |
| Chihou | 0.0005% |
Strategic Considerations
When to Attempt
- Multiple pairs in starting hand (toitsu-ba)
- Successfully complete 2 kans early
- Other players aren’t making kans
Progression
1st kan → Normal kan
↓
2nd kan → Start considering
↓
3rd kan → Fully commit to Suu Kan Tsu
↓
4th kan → The hardest partRelated Terms
- Kan: A set of four identical tiles
- Ankan: Concealed kan
- Rinshan Kaihou: Winning on the replacement tile after a kan
Summary
Suu Kan Tsu is the rarest yakuman in mahjong, requiring four kans and one pair. With an occurrence rate of about 0.00011%, it’s a legendary hand that most players will never complete. The main challenge isn’t just making four kans - it’s completing them before another player triggers Suu Kan Nagare. If you ever achieve this hand, it’s truly a once-in-a-lifetime accomplishment in mahjong.