A set of Mahjong tiles will usually differ from place to place. It usually has at least 136 tiles, most commonly 144, although sets originating from America or Japan will have more.
Mahjong tiles can be organized into several categories:
Suited tiles
The majority of Mahjong tiles are of a rank and a suit. There are three money-based suits of tiles (銅索萬), with ranks ranging from one to nine. There are four tiles of each rank and suit combination, thus there are 36 tiles in a suit, and 108 suited tiles in total. To refer to a suited tile, the rank is named, followed by the suit.
The circle suit (筒子, pinyin tǒngzi (barrel); also 餅/饼, pinyin bǐng (flatbread); Japanese 筒子 romaji pinzu) is represented by a series of circles.
 |
 |
 |
 |
 |
 |
 |
 |
 |
The 1 Circle is generally a large circle of multiple colors, while the rest of the circle tiles consist of smaller circles, each circle being of one color. The 2 Circle consists of a green and a blue circle, the 3 consisting of one blue, one green, and one red circle arranged diagonally (the order the circles appear in, as well as the orientation, differs between sets). The 4 Circle has two blue circles and two green circles, arranged in a rectangle with circles of like color in opposite corners. The 5 Circle is similar to the 4 Circle, with another circle (its color depending on the set) in the middle. The 6 Circle consists of two green circles at the top and four red circles in the bottom (with a space between the green and red circles). The 7 Circle is similar to the 6 Circle, but has 3 green circles arranged diagonally from top-left to bottom-right. The 8 Circle has eight blue circles arranged in a 2×4 rectangle. The 9 Circle has three each of blue, red, and green circles, with each color occupying a row. There is some space between each row, and the middle row is always of the red circles (the blue and green, of course, depends on the orientation of the tile).
Because of the large size of the circle in the 1 Circle, it is commonly nicknamed da bing (大餅 pinyin dàbǐng, lit. big pancake).
From the monetary origin of this suit, the circles represent the copper coins. (1銅=one copper coin).
The bamboo suit (索子, pinyin suǒzi (woven thread); also 條/条, pinyin tiáo (strip); Japanese romaji sōzu), with the exception of the 1 Bamboo, which is represented by a bird, is represented by outlines of sticks.
 |
 |
 |
 |
 |
 |
 |
 |
 |
The 2, 3, 4, 6, and 8 Bamboo are represented entirely out of blue and green sticks, while the middle stick in the 5 Bamboo, the top stick of the seven bamboo, and the sticks along the center column of the 9 Bamboo are red. Some sets may also have the sticks along the bottom row or center column of the 7 Bamboo in blue. The 8 Bamboo has its sticks forming an M-shape and its mirror image.
The 1 Bamboo, as it is often shaped as a bird, is often referred as the sparrow (麻雀 – má què). The rumour why the 1 Bamboo is different from others is to avoid cheaters from adding more Bamboo lines to the 1 Bamboo to change it into other Bamboo tiles.
From the monetary origin of this suit, the sticks are actually rope strings (索) that tie 100 Chinese copper coins together by the square holes in the middle. (1索=100銅) The repeated bumps in the sticks depict the individual coins in the strings, but they were mistaken as the knots on the bamboo plants, hence the English name of the suit.
The character suit, more appropriately known as the WAN Tiles (萬子/万子, pinyin wànzi, Japanese romaji wanzu or manzu) is represented by Chinese characters.
 |
 |
 |
 |
 |
 |
 |
 |
 |
Although some sets use Simplified Chinese characters, many use traditional Chinese characters as they are more complex and considered more aesthetically pleasing. The rank of the tile is represented at the top, in blue, with Chinese numerals, while the character below (萬 wàn, meaning myriad) is in red. Some sets use the character 伍 for five instead of 五.
The ones and nines of each suit (幺九, pinyin yāo jiǔ) are collectively referred to as the terminal tiles.
From the monetary origin of this suit, the wans (10,000) are actually 100 strings of coins described in the bamboo suit section above. One myriad equals ten thousand coins or 100 strings of 100 coins. (1萬=100索×100銅)
Honor tiles
Honor Tiles are tiles that do not have a rank or suit. They are divided into two categories, Wind tiles (風牌/风牌, pinyin fēngpái, Japanese romaji fompai or kazehai) and Dragon tiles (三元牌, pinyin sānyuánpái, Japanese romaji sangempai). There are four types of Wind tiles and three types of Dragon tiles, with four of each type of honor tile. Thus, there are 16 wind tiles and 12 Dragon tiles for 28 honor tiles.
The Wind tiles consist of four kinds of tile: East (東, dōng, Japanese romaji ton), South (南, nán, Japanese romaji nan), West (西, xī, Japanese romaji shā), and North (北, běi, Japanese romaji pei or pē).
 |
 |
 |
 |
Each type of Wind tiles corresponds to a point along the compass, written in blue traditional Chinese characters (even for sets where the Character tiles are written in simplified Chinese).
The three types of Dragon tiles are:
 |
 |
 |
- Red (紅中/红中, pinyin hóng zhōng, Japanese 中 romaji chun) – a tile with a red traditional Chinese character (中) or a red dragon. Some sets may also have a black letter C in a corner of the tile, denoting the first letter of the Wade-Giles romanization of 中 (chung).
- Green (青發/青发, pinyin qīng fā, Japanese 發 romaji hatsu) – a tile with a green traditional Chinese character (發), even for sets where the Character tiles are written in simplified Chinese. Often the variant character
(癶 over 弓矢 instead of 弓殳) is used. Because of its meaning (發財/发财, pinyin fā cái loosely means “to strike it rich”), a giant Green Dragon tile serves as a good luck charm in many Chinese households. Some sets, notably American, use a green dragon in place of the character. Some sets may also have a black letter F in a corner of the tile, denoting the first letter of the Wade-Giles romanization of 發 (fa), despite the fact that many believe that the F is taken from a form of Cantonese romanization (fat). - White (白板, pinyin bái bǎn, Japanese 白 romaji haku or shiro) – a tile which can be without any markings (白), although most modern sets employ tiles with a blue border to distinguish them from replacement tiles. Some sets may also have a black letter B in the center of the tile, denoting the first letter of the Wade-Giles romanization of 白 (bai). Japanese tiles of this kind have no mark on them, and are occasionally dubbed tofu (bean curd) in some Japanese mahjong clubs.
The use of the term “dragons” in the West is incorrect. The tiles represent 3 forms of life: the red dragon tile (hóngzhong) symbolizes the animal order, which includes humans and dragons; the green dragon tile (qingfa), symbolizes the plant order; and the white dragon tile ( báipí), symbolizes spiritual beings.
Flower tiles
Flower tiles (花牌 pinyin huāpái, Japanese hanahai or fapai) are further subdivided into groups. Each group contains four unique tiles, which are numbered from 1 to 4 or otherwise distinctly labelled. These tiles usually depict stylised representations of flowers in many colors (hence the name). Nevertheless, other non-floral themes also exist, which vary from set to set. The average set, if it contains flower tiles, will have two groups of flower tiles, differentiating the color and/or style of the labels. Common Chinese sets will have one set of flower tiles with blue Arabic numerals and the other set having red Chinese numerals, numbered one to four.
In mahjong solitaire, the two groups are often called Flower tiles (not to be confused with the blanket term for all groups of flower tiles) and Season Tiles (季牌 jì pái, Japanese 季節牌 kisetsuhai).
The four tiles in the Flower tile group, which correspond to the Four Gentlemen in Chinese art, are:
 |
 |
 |
 |
- plum 梅 méi
- orchid 蘭 lán
- chrysanthemum 菊 jú
- bamboo 竹 zhú
The four tiles in the Season tile group are:
 |
 |
 |
 |
- Spring 春 chūn
- Summer 夏 xià
- Autumn 秋 qiū
- Winter 冬 dōng
Some Singaporean Mahjong sets provide for a third group of flower tiles by adding two pairs of animal tiles. Some examples of tile pairs include:
 |
 |
 |
 |
- Cat (猫 māo) & Mouse/Rat (老鼠 láoshŭ)
- Cockerel (公鸡 gōngjī) & Centipede (蜈蚣 wúgōng)
- Rich Man & Pot of Gold
- Fisherman & Fish
Other sets may provide more groups of flower tiles.
Joker tiles
Unique to American sets are eight Joker tiles, tiles that simply say “Joker” in a diagonal pattern. Often in Chinese the words 百搭 bǎidā — ‘a hundred uses’ — are seen. Jokers are also used in certain variants of Southeast Asian and Chinese mahjong, including Shanghainese mahjong, which uses four Jokers. Joker tiles can be used to replace any tile in putting together a hand.
Source: http://en.wikipedia.org/wiki/Mahjong_tiles