Rules

Orbit is a Go variant in which players strive to enclose territory inside orbits and half-orbits.

An orbit is a cycle of same-coloured pieces that encloses one or more points. A half-orbit is a connected set of pieces that, together with one side of the board, encloses one or more points. The enclosed points may be empty or occupied by enemy pieces. The surrounding connection may include orthogonal and diagonal steps.

The following example shows an O orbit and two X half-orbits:

     A B C D E F G H I

  9  - - - - x - - x -  9
  8  - - - - x x - x -  8
  7  - - - - - - x - -  7
  6  - - o o - - - - -  6
  5  - o - - o - - - x  5
  4  - o - - o - - x -  4
  3  - o - o - - x - -  3
  2  - - o - - - - x -  2
  1  - - - - - - - - x  1
     
     A B C D E F G H I

Players take turns placing a piece of their colour on any empty point, provided that point does not lie within an enemy orbit or half-orbit. After each move, enemy pieces enclosed by orbits are captured and removed from the board.

The game ends when either the board fills up or all players pass in succession. The player with the most territory wins; territory is the total number of empty points exclusively within that player's orbits and half-orbits (shared territory does not count).

References and History

Orbit was designed by Steven Meyers.

Implementation and help file by Cameron Browne, February 2005.