In a Mah Jongg Game Set there are four pieces of each of these tiles, that is, there are four White Dragons, four Green Dragons, and four Red Dragons.
For scoring purposes the Dragons are known as the Superior Honour Tiles and this means that Dragon tile suits you collect will be assigned higher score values.
For the Dragon suit - you may collect Pungs, Kongs or a pair of identical Dragons (the latter only for the purpose of going Mah Jongg) - Chows are not allowed.
Chinese Character: "Chung"
The true name of this tile is represented by the Chinese character "Chung" which means centre or middle. The "Chung" character represents interpretation an arrow striking the centre of a target. The meaning of this tile is therefore - success or achievement.
This tile is the counterpart of the "The Green Dragon" tile which show the arrow about to leave the bow. It is commonly called "The Red Dragon" in western Mah Jongg sets because the "Chung" character is generally drawn in red ink.
Chinese Character: "Fa"
The true name of this tile is represented by the Chinese character "Fa" which means to commence. The "Fa" character is a stylised interpretation of a bow being drawn with an arrow about to be fired. The meaning of this tile is therefore - proceed, start or begin. It is commonly called "The Green Dragon" in western Mah Jongg sets because the "Fa" character is frequently drawn in green ink.
Chinese Character: "Pai"
Historically, the White Dragon tile used to be part of the spare tiles in a Mah Jongg set, but later became used in the game itself. The representation of the tile varies in Mah Jongg sets, it is shown as a blank (plain) tile: sometimes marked with the lettering "WHITE", or perhaps with a simple border enclosing the letter "B" (for Blank) or "P" (to represent the Chinese character "Pai"), or with a decorative border only. The White Dragon is a blank tile that represents the mysterious unknown.