A strategy in the board game "Risk" wherein one player quickly captures Japan at the beginning of the game, and proceeds to put all of his armies on the country each turn without attacking anywhere else for most of the game.
When most of the other players have been eliminated and the game appears to be drawing to an end, the player charges out of Japan and conquers most of Asia if not the entire game board.
The strategy is actually surprisingly effective, as players are focused on gaining bonuses early in the game and by the time they've laid out borders, the Japan Plan player's armies outnumber theirs.
It was created by a BC High School student who got bored with playing, and instructed the other players to just continually put all of his units on Japan. When he revisited the board hours later, he found his army force could easily capture the entire game board.