Penchan
A penchan machi 「辺張待ち」 is a common type of wait pattern. This wait pattern contains the tiles 1 and 2 of the same suit, or 8 and 9 of the same suit. The pattern is limited to waiting for the completion of the shuntsu with a 3 or 7. At maximum, only four tiles are available for completion.
| Kanji | 辺張 |
|---|---|
| English | Edge wait |
| Fu | 2 fu |
| Tile types waiting | 1 sided wait |
| Tiles available | 4 tiles |
| Pattern example |
  |
| Tenhou.net example | Penchan (1-2) |
Pattern
, winning tile: 
Penchan is often used for a 1-2 or 8-9 shape within the hand, even while the entire hand has not reached tenpai.
Fu
Because the winning tile does not complete a shuntsu which was completable on two sides, winning from a penchan awards 2 fu to the hand and does not count as pinfu. Sometimes, a winning tile can be interpreted to complete either a penchan or something else, and the higher-scoring interpretation will be used.
, winning tiles: or 
This hand qualifies for pinfu on both winning tiles. If a 3-pin is used, it is interpreted as completing the ryanmen 4-5 with the shuntsu 1-2-3 already in place. If it were interpreted as a 1-2 penchan winning with 3-pin and 3-4-5 already in place, the hand would gain 2 fu, but lose 1 han for not scoring pinfu.
, tsumo:
This hand, however, will interpret the 3-pin to complete the penchan 1-2 instead of the ryanmen 4-5. It doesn't qualify for pinfu anyway because of the 1-sou ankou. This interpretation makes the hand worth 40 fu instead of 30: It has 20 base fu, 8 fu from the ankou, 2 fu for winning by tsumo, 2 fu for the penchan machi, making 32 fu in all, rounded to 40.
Strategy
Penchan is considered to be a "bad wait", because it can only wait for a maximum of 4 tiles. Thus, penchans are worse for hand development.
Kanchan vs Penchan
A kanchan wait, while waiting for the same number of tiles, is considered stronger (better for efficiency) than penchan. This is because kanchans are easier to upgrade.
- A
kanchan can be upgraded by drawing 
, turning it into a (two-sided) ryanmen.
- A
penchan cannot be upgraded to ryanmen on its own. It must first draw a , turning it into a kanchan, then draw the to get a ryanmen.
As a penchan requires 2 tiles to be upgraded, it is inferior to keep before reaching tenpai. However, once you reach tenpai, both kanchan and penchan become effectively identical.
Suji
Penchan is a weak wait, but suji can enhance the wait. A discarded 6 tile may signal the 3 tile of the same suit as safe to others. Similarly, when waiting for a 7, the 4 would be discarded. For either case, players may utilize penchan to "suji trap" other players into discarding seemingly safe tiles.
Both chanta and junchan often, but not always, use penchan waits. Both these yaku rely on tiles near the ends (1,2,3) and (7,8,9). Not always but often enough, they end up using penchan waits during development and at tenpai.
External links
- Penchan in Japanese Wikipedia