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Sokoban (Sōkoban, warehouse keeper) is a type of transport puzzle, in which the player pushes boxes around a maze, viewed from above, and tries to put them in predetermined areas. Only one box may be pushed at a time, and boxes cannot be pulled. The numbers of boxes is equal to designated locations. The puzzle may have limited the number of steps. The puzzle is usually implemented as a video game.

Sokoban was created in 1981 by Hiroyuki Imabayashi, and was published in 1982 by Thinking Rabbit, a software house based in Takarazuka, Japan.

"Soko is the Japanese word for warehouse and Sokoban means warehouseman or storeman. The story goes as follows. A storeman is left in charge of an [...] warehouse, which consists of a number of rooms or chambers connected by doorways and corridors. Inside these rooms various packing cases have been left lying around and the storeman has been told that he must get them all into one particular chamber. The packing cases are very heavy and have no handles. The storeman is just strong enough to push them, but only one at a time; he cannot pull them. In order to push a packing case, the storeman needs to be able to get completely behind it. He cannot rotate them by pushing on their edges and then slip in behind. Obviously, if a packing case is pushed into a corner, it is stuck there.
The object of the exercise is to get all the packing cases [...] into [designated locations] [...] in one of the chambers. For convenience it is assumed that the storeman is the same size as a packing case and that he cannot jump over a packing case, nor squeeze between them unless there is at least the area of a packing case (one square) available. He must have a whole square behind a packing case to be able to push it from square to square."

Text is available under the Creative Commons Attribution-ShareAlike License; http://en.wikipedia.org/wiki/Sokoban