Mahjong solitaire

Mahjong solitaire is a matching game that uses a set of mahjong tiles rather than cards. It is also known as Shanghai solitaire, electronic or computerised mahjong, mahjong solitaire and, wrongly, as mahjong. The tiles come from the four-player game popular in East Asia known as mahjong.

The board is drawn in your browser, so JavaScript must be enabled. The rule of the game and its history, however, read fine without it.

144 tiles 0 open pairs 0 moves

Board

Changing the board deals a new game. The pagoda is the easier of the two: its layers are neatly centred rectangles, whereas the body of the turtle locks in long rows whose ends alone are open.

By finger: touch a tile to aim at it, then its twin. Touching the same one twice cancels the aim. With a keyboard: the arrow keys move from tile to tile, Enter aims and then confirms.

The flowers and the seasons are the exception: there is only one of each, so any flower matches any other flower, and any season any other season. Without that, eight tiles would never leave the board.

Players can open new tiles with every pair they clear. Taking the obvious pairs from the upper layers often ends the game early — that is, loses it — by leaving essential tiles covered.

The rule

The 144 tiles are laid out in a special pattern on four layers, face up. A tile is said to be open, or exposed, if it can be moved either left or right without disturbing the other tiles. The aim is to match open pairs of identical tiles and remove them from the board, thereby exposing the tiles underneath for play. The game is over when every pair of tiles has been removed from the board, or when no open pair is left.

What this game is not

Mahjong solitaire can be played using genuine tiles and a wooden frame to set them out. Usually, though, it is played in its electronic form as a computer game, which does away with the tedium of setting up and the temptation to cheat.

A deal that can always be solved

What is more, most implementations of this game lay the tiles out so that the game can be solved in at least one way.

This one can. The tiles are not thrown onto the board at random: the game is played first, on a full board of tiles that are still nameless, by lifting off seventy-two times two tiles that are open at the same moment — and only then is it decided which kind of tile stood in each of the two places. That sequence of removals is a legal game from beginning to end: the solution exists before the deal does.

What this changes can be measured. On the turtle, an attentive player finishes four games out of ten with this deal, against one in ten with a random one, and when he does get stuck he has twenty-six tiles left instead of forty-four. The check that produces these numbers is versioned in the repository and runs with one command.

What remains possible is blocking yourself: four identical tiles offer matches the solution had not planned for. That is the game, the article above warns of the trap, and that is what "Undo" is for.

The options of other versions

They may also offer hint and cheat options, such as the chance for the player to be shown a suggested pair, or to go back and undo moves already made.

What you are matching without knowing it

The tiles themselves really are Chinese. Here is what they say.

Suit	On the tile	Pinyin	Meaning	What is worth knowing
The characters	萬万	wàn	ten thousand	Nine tiles, from 一萬 to 九萬. The number is engraved above the character; this is the only suit spelled out in words, and that is where its name comes from. The site's own article sees the foot soldiers in it.
The circles	筒	tǒng	tube; pipe	Nine tiles, from one to nine circles. The word names the end of a tube — a pierced coin seen face on. The site's own article sees the shield in it.
The bamboos	索	suǒ	rope	Nine tiles, from one to nine sticks. They are also called 条 tiáo, the measure word for long objects. The one is not drawn as a stick but as a bird — 幺鸡 yāojī, "the bird tile" in the site's dictionary. The site's own article sees the spear in the bamboo.
The winds	東南西北东南西北	dōng nán xī běi	east, south, west, north	Four tiles, four copies of each. They give every player his seat and every round its name. The Chinese order of the compass points begins with east, not with north.
The dragons	中發白中发白	zhōng fā bái	centre, prosperity, white	Red, green and white. 中 is engraved in red, 發 in green, and the white dragon is a bare tile — sometimes a plain blue frame. The name "dragon" comes from the American dealers of the 1920s; in Chinese these are not dragons at all.
The flowers	梅蘭菊竹梅兰菊竹	méi lán jú zhú	plum, orchid, chrysanthemum, bamboo	Four unique tiles. They are the "four gentlemen" of scholar painting, a motif the site shows elsewhere. They are not kept in the hand: you lay them down and draw again.
The seasons	春夏秋冬	chūn xià qiū dōng	spring, summer, autumn, winter	Four unique tiles, played like the flowers. Each answers to one wind, and the one that answers to yours doubles your points.

The real mahjong, for four players »