Passage is a connection game played on a 20x20 square grid. Each player has an identical (except for color) set of polyominoes - three each of the seven shown. The pieces have semicircles along their edges.
Players are attempting to construct a path of their pieces between two opposite edges of the board. When pieces are next to each other their semicircles will join to form full circles. If a player can play a piece on top of an opposing piece so that at least two squares are covered and it forms more circles with adjacent pieces, the opposing piece is captured and replaced.
When a path between edges is formed (and can't be broken by an immediate capture) each player counts their longest path and the player with the longer one scores the difference. A series of games should be played to determine the overall winner.
The designer later (in Games & Puzzles #50) suggested playing with two copies of each piece instead, or using a 24x24 board.