What is Shuntsu (Sequence)?
Shuntsu (順子) is a combination of 3 consecutive numbered tiles of the same suit in mahjong. For example, 1-man 2-man 3-man (123m) or 4-pin 5-pin 6-pin (456p) are shuntsu.
Shuntsu is the easiest type of set to make and forms the core of efficient hand building. The name comes from “順” meaning “sequential order,” referring to tiles arranged in sequence.
Detailed Explanation of Shuntsu
Requirements for Shuntsu
- Must be numbered tiles of the same suit (man, pin, or sou)
- Must be 3 consecutive tiles (e.g., 234, 567)
- Cannot be made with honors (winds and dragons are not allowed)
Examples of Shuntsu
| Suit | Shuntsu Example | Notation |
|---|---|---|
| Man (Characters) | 1m-2m-3m | 123m |
| Man (Characters) | 7m-8m-9m | 789m |
| Pin (Circles) | 2p-3p-4p | 234p |
| Pin (Circles) | 5p-6p-7p | 567p |
| Sou (Bamboos) | 3s-4s-5s | 345s |
| Sou (Bamboos) | 6s-7s-8s | 678s |
How to Build Shuntsu
-
Draw by yourself (Tsumo)
- Draw the needed tile yourself
- The most basic method
-
Call Chi
- Use left player’s (kamicha) discard
- Have 2 tiles and get the remaining 1
Comparison: Shuntsu vs Koutsu
| Aspect | Shuntsu | Koutsu |
|---|---|---|
| Composition | 3 consecutive tiles | 3 identical tiles |
| Ease of Building | Easy | Difficult |
| Calling | Chi only (from left) | Pon (from anyone) |
| Yaku Impact | Required for pinfu etc. | Required for toitoi |
Usage Examples
Real Game Situations
Example 1: Hand Explanation
"I have 3 sequences, one more set until tenpai"
"I have a 234 sequence and a 56 ryanmen taatsu"Example 2: Chi Decision
"I have 23, so I can chi 1 or 4"
"This is a sequence-focused hand, let's chi actively"Example 3: Wait Explanation
"I have 123 and 789 sequences, ryanmen wait for 456"
"Built with sequences, so pinfu is also possible"Taatsu (Incomplete Sequences)
Incomplete Forms of Shuntsu
| Type | Explanation | Example | Wait |
|---|---|---|---|
| Ryanmen | Open-ended wait | 23 | 1 or 4 |
| Kanchan | Closed wait (middle) | 13 | 2 |
| Penchan | Edge wait | 12 | 3 |
Efficiency Ranking
- Ryanmen taatsu (Best)
- Kanchan taatsu (Average)
- Penchan taatsu (Worst)
Related Terms
- Mentsu: General term for 3-tile sets
- Koutsu: 3 identical tiles
- Taatsu: Incomplete set
- Ryanmen: Open-ended wait
- Chi: Call to make a sequence
Common Mistakes and Points to Note
Points Beginners Often Mistake
-
Sequence across different suits
- 1m-2p-3s is NOT a sequence
- Must be the same suit
-
Wrapping around 9-1-2
- 9m-1m-2m is NOT a sequence
- Numbers don’t wrap around
-
Sequence with honors
- East-South-West is NOT a sequence
- Honors can only make triplets
-
Chi restriction
- Can only chi from left player
- Often confused with pon
Yaku Using Shuntsu
Main Yaku Related to Sequences
| Yaku Name | How Sequences Are Used |
|---|---|
| Pinfu | All sequences + ryanmen wait |
| Sanshoku Doujun | Same number sequence in 3 suits |
| Ikkitsuukan | Same suit 123, 456, 789 |
| Junchan Taiyao | All sequences include 1 or 9 |
Strategic Points
Sequence-Focused Hand Building
-
Advantages
- Hand develops faster
- Easy to make ryanmen waits
- Good compatibility with pinfu etc.
-
Disadvantages
- Tends to be lower scoring
- Easier to read
-
Suitable Starting Hands
- Many simples (2-8)
- Many consecutive numbered tiles
Conclusion
Shuntsu is the most basic and important type of set in mahjong. Despite its simple composition of 3 consecutive tiles, it’s essential for efficient hand building. Beginners should first learn sequence-focused hand building to play mahjong smoothly. If you consciously build sequences from ryanmen taatsu, you’ll naturally create good waits.