The name means "fishing" and the game uses two sets of Chinese dominoes (64 tiles in all) with two or three players.
The tiles are arranged in a woodpile, four tiles high. Four stacks (16 tiles) are taken from one end and laid face up on the table. Each player then draws his hand; for three players, each draws two stacks (8 tiles); for two players, each draws three stack (12 tiles).
The idea is to match a tile in your hand to a tile that is face up on the table. Two tiles match when their pips have the same total, regardless of how the pips are arranged.
You can also match the [2-1] and [4-2] (Gee Joon or "supreme pair") together.
If a player is dealt a pair of [6-6], he may lay them down from his hand immediately.
In his turn, each player matches one of his tiles to one of the exposed tiles and collects the pair in front of him.
Whether or not he was able to make a match, he draws a single tile from the top stack at the end of the woodpile. If this new tile matches an exposed tile, the player collects this pair immediately. If this new tiles does not match an exposed tile, he leaves it face up on the table.
If there are two identical tiles on the table, a player who has a third identical itle can place it with the first two and later a player can capture these three with the fourth identical tile. This is clearly only possible with the civil series tiles - the doubles, [3-1], [5-1], [6-1], [6-4] and [6-5] - since these are the only tiles of which there are four identical copies in the set.
Play continues around the table until the woodpile is empty.
The little fish are tiles with less than eight pips. They score one point for every red spot they have, then the score is raised up to the nearest multiple of ten. For example, 3 red spots would become 10 points.
The big fish are tiles with eight or more pips. They score two points for every pip they have, regardless of color.
Each player adds these two scores together to get his final score. The winner is the highest score and each of the other players pay him the difference between his final score and their final score.
An earlier version of these rules of Tiu U was published in the Game Cabinet.