Machi

Machi 「待ち」, or "waits" in English, are patterns that can be used to form tile groups and/or pairs. They of are particular interest for tenpai hands, since a tenpai hand's wait determines which tiles it can win with.

There are 5 basic wait patterns. These patterns are the most frequent: they are comprised of only 1-2 tiles, and are not dependent on anything else in the hand. Basic waits can be combined in order to form "complex waits".

Overview

Many different patterns arise during hand development. Once a hand is in tenpai, being able to recognize your winning tiles is important, lest you miss a win. The most common patterns are given names to make them more recognizable.

When a hand is in tenpai:

• N-sided wait refers to the number of types of tile a hand can win with. A hand that waits for 1m and 4m would be 2-sided. The largest sided wait is kokushi musou, which has a 13-sided wait.
• N-tiles available refers to the number of tiles a hand can win with. A hand that waits for 1m and 4m would wait for 8 tiles at maximum (4 copies of 1m, 4 copies of 4m). This number decreases if the winning tiles are discarded, visible in others' tile calls, or if the winning tiles are included in the hand. So if a hand that waits for 1m and 4m already has two copies of 1m, it would wait for 6 tiles at maximum. A hand can wait with 0 tiles remaining, a state known as karaten.

Even before reaching tenpai, understanding waits are important. Wait patterns are used to form tile groups, so a hand will gather many wait patterns before reaching tenpai. Keeping better waits in your hand will allow you to to complete your hand faster.

Hands with many tiles of the same suit, most notably chinitsu hands, are notorious for their complex waits, due to the many different ways the hand can be interpreted. Such hands can be difficult to figure out without the help of computer software.

Basic wait patterns

There are five basic wait patterns. These are made out of 1 or 2 tiles. Upon tenpai, they only look to complete either the last tile group or the pair. All complex waits can be derived from the basic waits.

Romaji	Kanji/Kana	Translated	Pattern	No. Sides	Max. tiles	Fu
Ryanmen	両面	Open	Waiting for:	2	8 tiles	0 fu
Shanpon	双ポン	Dual pair	Waiting for:	2	4 tiles	0 fu
Kanchan	嵌張	Closed/Middle	Waiting for:	1	4 tiles	2 fu
Penchan	辺張	Edge	Waiting for:	1	4 tiles	2 fu
Tanki	単騎	Pair	Waiting for:	1	3 tiles	2 fu

Each of these wait patterns are worth a set amount of fu. For the purposes of fu counting, a complex wait can always be interpreted as one of the basic waits. (If multiple interpretations are possible, the highest scoring one is used. This may or may not be the one with the most fu.)

Assuming all else equal, ryanmen is the strongest of the basic wait patterns, with twice the number of tiles as the others. Shanpon is stronger than the others, since waiting on 2 types of tile is better than 1, and shanpon can wait with honor tiles. Kanchan and penchan are equally strong in tenpai; kanchan is stronger before tenpai, since it is easier to upgrade into ryanmen. Tanki is the weakest, but can be surprising.

Named combinations

The basic patterns can be combined for more complex patterns. The wait patterns listed here have taken on names.

Name	Kanji/Kana	Header text
Nobetan	延べ単 ノベタン	Waiting for:
Standard Sanmenchan	狭義の三面張	Waiting for:
Sanmentan	三面単	Waiting for:
Entotsu	煙突系 エントツ	Waiting for:
Aryanmen	亜両面	Waiting for:
Ryantan	両単	Waiting for:
Pentan	辺単	Waiting for:
Kantan	嵌単	Waiting for:
Kantankan	嵌単嵌	Waiting for:
Tatsumaki	竜巻	Waiting for:
Happoubijin	八方美人	Waiting for:

Yakuman patterns

These three unique patterns are linked to specific yakuman. A yakuman is ensured no matter which tile is scored; under some rulesets, the latter two patterns are worth a double yakuman.

The latter two patterns are the widest in the game. The widest non-yakuman wait is an 8-sided wait.

Kokushi musou

Main article: Kokushi musou

Waiting for:

Kokushi musou 13 machi

Main article: Kokushi musou

Waiting for:

Chuuren poutou kyuumen machi

Main article: Chuuren poutou

Waiting for:

Other complex patterns

Main article: Complex waits

These combinations involve patterns that do not have specific names. Instead, they use combined forms of the other patterns. Furthermore, they mostly consist of consecutive, or closely consecutive, numbered tiles. Recognition of these patterns can produce some significantly powerful waits, which may be immune to suji and have large numbers of waiting tiles.

Related terminology

Karaten

Main article: Karaten

Karaten 「カラテン」, or empty tenpai, is the case where there are no tiles left to win with, due to all potential winning tiles already having been used in the player's hand, a discard pool, a called group, or visible as dora indicators. In some rulesets, a hand in this state is considered noten at an exhaustive draw.

Takame and yasume

Main article: Takame and yasume

Takame is a potential winning tile which is worth more points than another, called yasume.

External links

• 聴牌

Machi in Japanese Wikipedia

• ReachMahjong wait guide

Forum list of various patterns

• Tenhou wait calculator

Wait survey quiz in Tenhou.net