|Tile types waiting||2 sided wait|
|Tiles available||8 tiles|
|Tenhou.net example||Using riichi|
Ryanmen 「両面」 is the most commonly occurring wait pattern in the game. Commonly referred as the "open wait", this pattern involves two consecutively numbered tiles, waiting on the "outside" number. For example, a 3-4 needs either a 2 or a 5 in order to form tile groups of either 2-3-4 or 3-4-5. By far, this is the most efficient wait pattern, as it uses just two tiles while waiting on a maximum of eight possible tiles.
Always, ryanmen wait for two tiles. In addition, two ryanmen patterns may combine to form a ryanmenten, which waits for 3 tiles instead of two.
Due to its relatively ease, the ryanmen pattern is not awarded any fu. The inability to gain fu based on ryanmen makes it an essential component to the yaku, pinfu. The yaku, pinfu, requires ryanmen, because the waiting pattern does not produce fu. Ryanmenten is also allowed, as nested ryanmen do not produce fu either.
Ryanmen is the most common wait pattern, due to both convenience and probability.
Ryanmen is directly related to suji, or the mahjong intervals. At any time, ryanmen waits on a pair based on the three intervals of: 1-4-7, 2-5-8, and 3-6-9.
In this example, the consecutive 2-3 needs either of the two waiting tiles in order to complete the sequence. The 1 and 4 is included in the 1-4-7 interval.
Due to the easy of use, ryanmen waits are by far the most commonly used wait pattern. Its biggest advantage stems on the maximum 8-tile count on two tile types. This is assuming both types are live tiles. In addition, the yaku pinfu requires ryanmen. making it one of the more frequently used yaku. As a two-tile pattern to complete a sequence, it is also a very compact shape leaving plenty of room to develop numerous hand patterns with the rest of the hand. In other words, it is a very efficient waiting pattern to use. This concept is applicable whether the hand is tenpai or not.