What is Ankan?
Ankan (Concealed Kan) is declaring a kan (quad) using only tiles from your own hand - all 4 identical tiles without calling from others’ discards. It’s called “concealed” because it doesn’t use others’ tiles.
Ankan is unique because it maintains your menzen (concealed) status, allowing you to still riichi. It can even be done after riichi under certain conditions.
Basic Rules
Ankan requirements:
1. Have 4 identical tiles in hand
2. Declare on your turn after drawing
3. Say "Kan"
4. Reveal the 4 tiles (2 face-down)
5. Draw rinshan tile
Types of Kan Compared
| Type | Tiles Used | Menzen | After Riichi |
|---|
| Ankan | 4 from hand | Maintained | Conditional |
| Daiminkan | 3 hand + 1 discard | Broken | No |
| Shouminkan | Pon + 1 hand | Already broken | No |
How to Display Ankan
Standard display:
┌─┬─┬─┬─┐
│ x │ O │ O │ x │ ← 2 face-down
└─┴─┴─┴─┘
*Two tiles face-down (usually outer tiles)
*Shows it's a concealed kan
Benefits
Ankan advantages:
1. Maintains menzen status
- Can still riichi
- Menzen tsumo still valid
2. Increases dora
- Kan dora revealed
- Kan ura dora too
3. Get rinshan tile
- Chance for rinshan kaihou
- Extra draw
4. More fu
- Ankan = 16 fu
- Terminal/honor ankan = 32 fu
Drawbacks
| Drawback | Effect | Impact |
|---|
| Fixed hand | Can’t change | Less flexibility |
| Weaker defense | Fewer tiles | Harder to fold |
| Information leak | Shows 4 tiles | Easier to read |
| Dora for everyone | Others benefit | Risk increase |
Ankan After Riichi
Conditions for Post-Riichi Ankan
Can ankan after riichi only if:
1. Wait doesn't change
- Same tile composition
- Same waiting tiles
2. Only fu increases
- Score goes up
- But shape stays same
Examples
| Hand | Draw | Ankan | Allowed? |
|---|
| 1112345m | 1m | 1m kan | No (wait changes) |
| 111222m33s | 1m | 1m kan | Yes (wait unchanged) |
When to Ankan
Good Timing
Consider ankan when:
1. You have 4 dora
- 16 fu + 4 dora
- Huge points
2. Need safe tiles
- Hope for good rinshan
- Defensive reason
3. Need more fu
- Push 30→40+ fu
- Score upgrade
4. Targeting rinshan kaihou
- Romance play
- One-shot reversal
When to Avoid
| Situation | Reason |
|---|
| Good wait shape | Prioritize winning |
| Others in riichi | Kan dora is risky |
| Last round | No time for extras |
Fu Calculation
Ankan fu values:
Regular ankan: 16 fu
Terminal/honor ankan: 32 fu
Example: White dragon ankan
Base: 16 fu
Honor: ×2
Total: 32 fu
| Yaku | Ankan Role |
|---|
| Rinshan Kaihou | Win on rinshan tile |
| Sankantsu | 3 kans (ankan counts) |
| Suukantsu | 4 kans (ankan counts) |
| Suuankou | Ankan counts as ankou |
Summary
Ankan (concealed kan) uses 4 identical tiles from your hand, maintaining menzen status - the only kan type that does. It increases dora, gives a rinshan draw, and adds significant fu. However, it fixes your hand and can benefit opponents too.
Remember: “ankan = menzen maintained” and “2 tiles face-down when displayed.” While powerful, timing matters - especially after riichi, where wait must remain unchanged. Learn to judge situations wisely for effective ankan use.