Mahjong or Mah Jongg as it is sometimes known, is an ancient Chinese game for 4 players using engraved tiles. These are traditionally made of ivory and bamboo, but modern sets are made of bone and wood, or even just plastic. The word ‘mahjong’ (meaning ‘sparrows’) derives from the sound made when the tiles are mixed around.

The Tiles : In a standard set there are 144 tiles (excluding jokers or spare tiles). There are 3 suits – bamboos, circles and characters. They each contain tiles numbered 1 to 9, with four of each number. Circle tiles have the corresponding number of circles engraved on them. Bamboo tiles have the correct number of bamboo shoots, except the 1 Bamboo which has a picture of a peacock. Character tiles have the Chinese character corresponding to the number. All three suits (at least in England) have the English numbers written on as well. There are also the four winds – North, East, South, West – four of each, which each have the Chinese characters (as well as the English letters, N,E,S,W) engraved on them. There are three dragons - Red (a rectangle with a line through), Green (a random scribble) and White (either a blank tile or one with a black frame). There are four of each of these as well. The dragons sometimes have English letters on – C on Red, F on Green, B on White. Finally there are four Seasons and four Flowers , with varying pictures, both numbered 1 to 4.

Seating : Mahjong should be played at a square table, with one player on each side. One player will be East (no. 1). Going round the table anticlockwise, the players will be South (no. 2), West (no. 3) and North (no. 4). Note - the directions are NOT the same as the points of the compass – North and South are the other way round.

Setting-up : Having removed the tiles from their box, you place them all face down and mix them up for a while (making sparrow-like sounds). Then each player builds his own wall. This considers of a stack of tiles, 18 long and 2 high. Once the four walls have been built, they are moved together into a square, meeting at the corners (so as not to let the dragons in). For the first game, each player rolls two dice and whoever rolls highest is East and Banker. East then rolls again, to determine were to take tiles from. He counts round anticlockwise, starting with his own wall, until he reaches the number rolled. He then rolls yet again, and counts that number clockwise along the wall. This stack (of two tiles) he takes out of the wall and places the two tiles seperately on the wall anticlockwise from the gap, the bottom tile being placed further away. This end of the wall is called the dead wall. East then takes the two stacks to the left. Then South takes 2 stacks, then West, then North. This is done three times. Then each player takes one more tile, and finally East takes another one, so that East has 14 tiles and the other players have 13 tiles. Each player should stand his tiles upright so that only he can see what they are. Finally the game can begin.

Playing : The game begins with East discarding a tile, saying what it is, and placing it in the middle of the walls. (In China they place the tiles face down, but here it is more normal to leave them face up, to make the game simpler). Then South picks up a tile going clockwise round the wall, and then discards one. The play continues like this, each player, going round anticlockwise, picking up a tile from the wall and discarding one. The object of the game is to get a hand consisting entirely of sets of 3 and runs of 3, with one pair. These are the different options:

PUNG : This is a set of three of the same tile. You can get a pung of any tile (except the flowers and seasons). There are two ways of getting a pung:
1. If you have 2 of the same tile in your hand already, and someone else discards another, you can say ‘Pung’, pick the tile up, and place the set of 3 on the table beside you. You then discard normally, as if it were your turn, and the play continues round the table.
2. You can start with 3 of the same tile in your hand, or can complete the pung by picking the 3rd tile off the wall. These are concealed pungs, and are better than normal pungs. You should not put them down on the table when you get them.

KONG : This is a set of four of the same tile. Again you can get a kong of any tile, except flowers and seasons. There are three ways of getting a kong:
1. If you already have a concealed pung in your hand, and someone else discards the 4th tile of that kind, you can say ‘Kong’, pick the tile up and place all 4 on the table beside you. You then pick up another tile from the dead wall (not from where you normally take tiles) and discard as if it were your turn.
2. If you already have a pung down on the table, and you pick up the 4th tile from the wall, you may put it down with the other three. You then pick up another tile from the dead wall and then discard as normal.
3. If you start with, or pick up a complete kong in your hand. This is a concealed kong and is better than a normal one. You do put a concealed kong down, and pick up another tile from the dead wall and then discard one.
As you can see, you always pick up a tile from the dead wall when you get a kong. This is so you have the right number of tiles in your hand for going mahjong.
Note: If you already have a pung down, and someone discards the 4th tile, you CANNOT pick it up to make a kong.

CHOW : This is a run of 3 tiles in the same suit. You cannot get a chow of winds or dragons. There are two ways of getting a chow:
1. If you already have two tiles in the run, and the person before you drops the 3rd, you can chow it, placing it on the table. You cannot chow the tile if either of the other two players discard it, only if the person to your left does. If someone wants to pung the same tile, they get priority.
2. If you get a run of three in your hand, you should not declare it but can keep it has a chow. A concealed chow is no better than a normal chow
Note: Chows are not nearly as good as pungs or kongs. They are simply useful for getting going mahjong quickly.

Flowers and Seasons : These are different from the other tiles. If you start with one (or more) you declare it (put it on the table beside you)on your first turn. If you pick one up, you declare it immediately. You then pick up another tile off the dead wall to replace it, and continue as normal
Note: Flowers and Seasons are simply bonus tiles, with no skill involved in getting them. Therefore in some games they are not used at all.

Going Mahjong : The game ends when someone goes mahjong. This happens when their hand (including the tile they have just picked up) consists of 4 sets (either pungs, kongs or chows) and a pair. The pair must be two of same tile, it cannot be a run of 2. When you are one tile away from mahjong, you are ‘calling. It is possible to be calling for more than one tile (eg if you have 3 sets and 2 pairs, you can go mahjong with another tile for either pair.) There are three ways to go mahjong:
1. You can get the tile you need when you pick up
2. You can use someone else’s discard to go mahjong. Whoever’s discard it is, you can pung, chow or even make a pair with it. If you are going mahjong with a chow, it does not need to be the person on left who discards the tile you need, you can pick it up whoever discards it.
3. If you get a kong, or a flower or season, you can go mahjong on the tile you pick from the dead wall.
When you go mahjong you lay your hand down on the table, and so does everyone else. Then each player scores up his hand, and works out how much he needs to pay everyone. If you get down to the 14th last tile in the wall, and no-one has gone mahjong, it is a wash-out and nobody gets any points.

Scoring : Each player when he has laid his land down, counts up how many points he has got. Scoring systems differ greatly, but these are the usual point values:

For all hands:                    Declared    Concealed
Normal Pung                           2           4
Pung of 1s, 9s, winds or dragons      4           8
Normal Kong                           8          16
Kong of 1s, 9s, winds or dragons     16          32
Pair of dragons, or own wind                      2
Each season or flower                 4       

Only for mahjong hand: 
Going mahjong                        20
Mahjong with only possible tile       2
Mahjong with tile from wall           2
All Pungs                            10
All Chows                            10
In addition to normal points, you can also get doubles. These double your total score (if you have 2 doubles they quadruple your score etc):
For all hands:
Pung (or kong) of dragons or own wind        1 double
All one suit, with winds and dragons         1 double
Own flower or season                         1 double
Complete set of flowers or seasons           3 doubles

For mahjong hand:
Going mahjong from dead wall                 1 double
Going mahjong with last tile from wall       1 double
Going mahjong with final discard             1 double
Whole hand concealed                         1 double
All 1s, 9s, Winds and Dragons                1 double
All one suit, no winds, no dragons           3 doubles
Finally there are certain limit hands. These are either worth 3000 or 1000 points. Generally they are rather odd hands which often with normal scoring would be worth very little. Which ones are acceptable vary from game to game.
These are the ones that are almost always played:

For 3000 points:
Heaven's blessing - East goes mahjong with the hand he is dealt
Earth's blessing - North, West or South goes mahjong on first discard
13 Wonders - One of each 1, one of each 9, one of each Wind, one of each Dragon, and a pair of any of them

For 1000 points:
Three great scholars - Pungs (or kongs) of all 3 Dragons, another pung and a pair.
Four blessings - Pungs (or kongs) of all 4 Winds and a pair.
Gates of Heaven - Concealed pung of 1s, concealed pung of 9s, a run from 2 to 8, all in the same suit
Seven Pairs - Seven pairs of any tiles.

Other optional limit hands:
For 3000 points:
Twofold fortune - A player completes a kong, picks a tile from the dead wall which completes another kong, picks another tile from the dead wall and goes mahjong.
Gathering the plum blossom from the roof - A player is calling for the 5 of circles, and picks it from the dead wall when he gets a flower, season or a kong.
Plucking the moon from the bottom of the sea - A player is calling for the 1 of circles, and picks it up as the last tile in the wall.

For 1000 points:
Knitting - Seven pairs, each consisting of 2 tiles of the same number, but both from different suits. The pairs must all consist of the same two suits.
Triple knitting - Four sets of three, each set having one tile of the same number from all three suits. And a pair.
Buried Treasure - Concealed pungs and a pair in one suit with winds and dragons
Fourfold plenty - Four kongs and a pair
Heads and Tails - Pungs (or kongs) and a pair, all of 1s and 9s
Wriggling Snake - Pair of 1s, a run from 2 to 9 all all in the same suit and one of each of the winds.
Imperial Jade - Pungs (or kongs) of the green tiles (Green Dragons, 2s, 3s, 4s, 6s and 8s of bamboo) and a pair.
Note: You can always choose to get the face value of your hand rather than the limit, if it is larger. Only the person who goes mahjong can get a limit hand, with the exception of 3 Great Scholars, 4 Blessings and 13 Wonders, which score as a limit hand even if you do not go mahjong.

Settling Up : Once everyone's scores have been calculated, they pay each other the required amount (either in points, scoring sticks, or even real money). The amount needed is calculated as follows:
1. The other 3 players each pay the person who went mahjong his total score. He does not pay anyone anything.
2. These 3 players pay each other the differences between their scores (the person with the higher score gets payed by the person with the lower score)
3. The banker receives and pays out double the normal amount. If he owes money he must pay twice that amount, if he is owed money he must be payed twice that amount.

Once everything has been settled, you go onto the next round. South becomes East, and the other positions also move round. If the banker (East) has gone mahjong, or it is a wash-out, the positions do not change. You rebuild the wall, and start again. Generally you play in rounds where a round ends when everyone has been banker.

Tactics : There is little point in discussing tactics, since they are very subtle, and you really have to play the game a lot to fully understand them. I will just mention a few points:
1. It is generally a good idea to try and go mahjong. Going mahjong means everyone else pays you.
2. Pungs are always better than chows (They score points). Chows are only good if you have a bad hand and want to get mahjong as quickly as possible.
3. If you start with a reasonable hand, it is often a good idea to go for several doubles to get more points (ie get all the same suit, pungs of dragons).

It is also possible, though not as good, to play with 3 players, where one wind, flower, and season belong to no-one.

Finally an entirely random and very unlikely piece of scoring I forgot - If banker goes mahjong 13 times in a row, he gets 7 doubles added to his 13th hand.