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Osbox Cameron Browne (c) 2008 |
Osbox is a pure strategy game in which two players push knotwork |
Rules
Pieces: Players share a common pool of six-sided Osbo dice showing knot segments on each face. Note that two of the faces are identical.
The six faces of an Osbo die.
Start: The game is played on a 4x4 square board which is initially empty. The first player (Horz) owns the left and right sides and the second player (Vert) owns the top and bottom sides. Players can only move along their home sides.
Play: Players take turns placing a die of their choice along one of their home sides and pushing it onto the board, as shown below. The die is pushed one space only.
Horz pushes a die onto the board.
Pushing a die onto the board may cause existing dice to be pushed along the same row/column, as shown below. Path segments do not need to match those on neighbouring dice, but dice cannot be pushed onto rows/columns that are full.
The mover scores points for each path closed by their move which passes through more than row and more than one column. A path's score is given by the number of crossings it contains, with self-crossings counting twice. Scoring paths are removed from the board as they occur.
A scoring move that pushes existing dice across to complete a knot.
Horz scores 8 points in the above example for completing the larger knot on the right which is then removed from the board. The smaller knot on the left does not score any points as it lies along a single row.
Aim: The game ends when the board is full and is won by the player with the highest score. The game is tied if scores are equal.
Notes
The fact that paths cannot lie completely within a single row or column ensures that players cannot simply push a thin knot along a single row/column to score it multiple times and reduces the number of cheap points from trivial pairings along the board edges.
The capture rule makes Osbox a sort of celtic knotwork Tetris. Each scoring move frees up the board, making games longer and more complex hence smaller boards can be used (e.g. 4x4). This rule introduces some interesting tactics in that players may tempt the opponent into completing small knots whose removal opens the way for larger knots next turn.
Scoring may be simplifed to the number of dice captured each turn rather than completed path length (Horz would instead score 5 points in the example above). This form of scoring is more intuitive and easier to calculate.
Variants
Any Side: The current player may enter their die from any side of the board, not just their own side.
Multiplayer Osbox: There's no reason that Osbox should not work with three or four players each owning a single board side. Then again, there's no reason that it should work either.
History
Osbox rules copyright (c) Cameron Browne, April 2008.
Osbox is a pure strategy game intended for players interested in the Osbo dice but who don't like randomness in their games. Osbox is similar in principle to a knotwork version of Tetris as suggested by Dan Isdell.