What is Kiken-hai?
Kiken-hai (dangerous tiles) are tiles with high probability of being an opponent’s waiting tile, carrying significant deal-in risk. Especially after riichi or when opponents are clearly in tenpai, these tiles are likely to result in dealing into their hand.
Correctly identifying dangerous tiles is the first step to better defense. It’s the opposite of “safe tiles” and essential for winning at mahjong.
Danger Assessment Factors
| Factor | Danger Level | Reason |
|---|---|---|
| Not in discards | High | Opponent may hold it |
| Middle tiles (3-7) | High | Easy ryanmen waits |
| Dora-related | High | Targeted tiles |
| Flush color | Very high | Honitsu/Chinitsu risk |
| No suji | High | Ryanmen possibility |
Safety Scale
← Safe ──────────────────── Dangerous →
Genbutsu > Honor(live) > Terminals > Outside > Middle > Dora areaTypes of Dangerous Tiles
By Situation
| Situation | Dangerous Tiles | Reason |
|---|---|---|
| After riichi | All middle tiles | Ryanmen possibility |
| Flush signs | That suit | Likely waits |
| Dora pon | Dora surroundings | Collecting related |
| Late game | All live tiles | Reason they’re kept |
By Number
Danger level (high → low):
4・5・6 > 3・7 > 2・8 > 1・9
Reason:
- 4-6 most likely ryanmen
- 3・7 relatively dangerous
- 1・9 hard to use in sequencesIdentifying Dangerous Tiles
Reading from Discards
Signs of increased danger:
-
Unnatural discards
- Cutting good tiles
- Not playing naturally
-
Flush signs
- Only 2 suits discarded
- Third suit is dangerous
-
Sequential early cuts
- Terminal-first discards
- Tanyao type - middle dangerous
-
Keeping honors
- Yakuhai back possible
- Even honors dangerous
Post-Riichi Danger
| Type | Danger | Response |
|---|---|---|
| Riichi tile surroundings | Extreme | Absolutely avoid |
| No-suji middle tiles | Extreme | Find genbutsu |
| Dora indicator area | High | Be cautious |
| Late game live tiles | High | Avoid if possible |
Defensive Play
Betaori Basics
Priority order:
1. Genbutsu (100% safe)
2. Passed suji tiles
3. Early discard surroundings
4. Honor tiles (watch live ones)
5. Terminal tilesPush/Fold Decision
| Your Situation | Response | Reason |
|---|---|---|
| High hand tenpai | Push | Worth the risk |
| Cheap hand tenpai | Fold | Risk too high |
| Iishanten | Usually fold | Still far |
| Bad wait | Careful | Hard to win |
Danger Probability
Estimated Deal-in Rates
| Tile Type | Deal-in Rate | Notes |
|---|---|---|
| No-suji 4-6 | 15-20% | Most dangerous |
| No-suji 3・7 | 10-15% | Dangerous |
| No-suji 2・8 | 5-10% | Somewhat dangerous |
| No-suji 1・9 | 3-5% | Relatively safe |
| One-suji | 3-8% | Situation dependent |
Special Dangerous Tiles
Often Overlooked
-
Dora indicator
- Looks safe itself
- Surroundings dangerous
-
Kanchan gaps
- Dangerous despite suji
- Easy to overlook
-
Hell wait
- 3 visible tiles
- Last one still out there
-
Yakuman tiles
- Honor tile danger
- Special waits
Common Mistakes
-
Over-trusting honors
- Live honors dangerous
- Yakuhai especially
-
Terminal safety myth
- Penchan waits exist
- Kokushi too
-
Early game carelessness
- Quick riichi happens
- Always stay alert
-
Suji misconception
- Not foolproof
- Useless vs kanchan/shanpon
Related Terms
- Anzen-hai: Safe tiles
- Genbutsu: Safest tiles
- Suji: Safety reading method
- Oshi-hiki: Push/fold decisions
- Betaori: Complete defense
Summary
Kiken-hai are tiles with high deal-in probability, especially middle tiles (3-7), live tiles, flush-color tiles, and dora surroundings. Beginners should remember “middle tiles are dangerous against riichi” and develop the habit of cutting from safer tiles like genbutsu and honors. Correctly identifying and avoiding dangerous tiles reduces deal-ins and improves results.