Gukei (Bad Shape) - Inefficient Wait Types in Mahjong

What is Gukei?

Gukei (bad shape) refers to wait shapes with few winning tiles, meaning inefficient waits. Compared to ryokei (good shape) like ryanmen (two-sided wait), gukei includes kanchan, penchan, shanpon, and tanki waits.

While “gukei” literally means “foolish shape,” it’s not always bad - in some situations, gukei can be advantageous.

Types and Tile Counts

Wait Type	Example	Waiting Tile	Max Tiles
Kanchan	13 waiting for 2	2 only	4 tiles
Penchan	12 waiting for 3	3 only	4 tiles
Shanpon	11 and 99	1 or 9	2 each (4 total)
Tanki	East single	East only	3 tiles
Nobetan	1234	1 or 4	3 each (6 total)

Comparison with Good Shape

Ryokei (Good Shape):
- Ryanmen: 23 waiting for 14 (max 8 tiles)
- Sanmenchan: 2345 waiting for 147 (max 12 tiles)

Gukei (Bad Shape):
- 4 tiles or fewer
- Lower win probability
- But harder to read

Gukei Characteristics

Feature	Merit	Demerit
Few wait tiles	Hard to read	Hard to win
Unusual shape	Unexpected	Inefficient
Riichi hesitation	Can play defensive	Less offensive
High/low options	Strategic choice	Complex decisions

Each Gukei Type

Kanchan Wait

Examples:
13 → waiting for 2
46 → waiting for 5
79 → waiting for 8

Features:
- Most common gukei
- Max 4 tiles
- Waiting for middle of sequence

Penchan Wait

Shape	Wait	Feature
12	3 wait	Edge-heavy
89	7 wait	Edge-heavy
23 (four 1s visible)	4 only	Wall-limited

Shanpon Wait

Examples:
11m 99s → 1m or 9s
East East, South South → East or South
55p 88p → 5p or 8p

Features:
- Two pairs
- Max 2 each (4 total)
- Good with toitoi

Tanki Wait

Type	Example	Max Tiles
Honor tanki	East wait	3 tiles
Number tanki	5m wait	3 tiles
Hell tanki	3 visible, 1 left	1 tile
Naked tanki	13 calls, 1 wait	Depends

Gukei Strategy

When to Riichi with Gukei

Worth riichi when:
1. High value (mangan+)
2. Dealer seeking renchan
3. Point deficit requires it
4. Waiting on opponent's genbutsu
5. 3+ tiles remaining

Avoiding Gukei

Stage	Counter	Example
Early	Prioritize ryanmen taatsu	Keep 23, cut 13
Mid	Cut gukei-prone tiles	Isolated 4s and 6s
Late	Wait for shape change	One more turn
Tenpai	Consider wait selection	Take the high wait

Using Gukei Advantages

Leverage gukei benefits:
1. Hard to read
   - Suji reading ineffective
   - Unexpected wait

2. Likely to be discarded
   - Early-cut honors
   - Isolated 4-6

3. Hard to deal into
   - Seems safe
   - Close to genbutsu

Shape Improvement

Changing to Good Shape

Current Shape	Draw	Result	Outcome
13 (kanchan)	4	134	Becomes 25 ryanmen
12 (penchan)	4	124	Becomes 3 tanki
11/99 (shanpon)	2	112/99	Becomes 3 tanki
East (tanki)	East East	East triplet	Ankou completed

Furiten Issues

Gukei easily becomes furiten:
- Cut one kanchan tile
- Cut one shanpon tile
- Changed from ryokei to gukei
- Missed ron, now furiten

Riichi Decision Criteria

Factor	Riichi	Dama
Value	High (3900+)	Low (1000)
Remaining tiles	3+	1-2
Turn	Early (turn 6-)	Late (turn 12+)
Opponent state	Quiet	Someone in riichi

Probability Theory

Win probability estimate (4 tiles in wall):
- Ryanmen: ~50% (4 of 8)
- Gukei: ~25% (2 of 4)
- Hell wait: ~6% (1 only)

*Depends on remaining turns

Mahjong Wisdom

Teachings

“Gukei riichi takes courage”
- Sometimes bold action needed
- High value justifies it
“If gukei, make it valuable”
- Cheap gukei is a loss
- Risk vs. return
“Waited for ryokei, got gukei”
- Don’t be too greedy
- Timing matters too

Ryokei: Good wait shape
Ryanmen: Basic good shape
Kanchan: Gap wait
Penchan: Edge wait
Shanpon: Two-pair wait
Tanki: Single wait

Summary

Gukei means wait shapes with few winning tiles like kanchan, penchan, shanpon, and tanki. While less efficient than ryokei, they have the advantage of being harder to read.

Beginners should first understand the difference between gukei and ryokei, aiming for ryokei tenpai. However, high-value gukei or situational gukei plays require judgment. Master both avoiding gukei and leveraging it - these skills are the path to mahjong improvement.