The Rules for MBrane

These are the rules as played at Boardspace.   

The game is for two players, red and black.  

a standard 9x9 Sudoku board.
81 tiles, 9 of each number from 0-8, red numbers on one side and black on the other.

Object of the game:
The object of the game is to control as many of the 3x3 regions on the board as possible.  Control
is determined in the resolution phase, but is based on the sum of tiles placed in each region, plus
influence cast into each region by tiles in adjacent regions.

Set up:
Initially the board is empty.  

Placement Phase:
Players alternate placing any tile, with their color up, observing the standard sudoku riules of placement,
until no more tiles can be placed.   Unlike solitaire sudoku, there probably will be a few spaces that cannot be filled.

Pie Rule:
After the first tile is placed, the second player can either place his first tile, or take over playing the other
color with the first tile as his first move.   Intuitively, one might judge the first player has an advantage; for
example by placing an 8 in a corner of the center region.   This rule allows the first player to switch sides
if he thinks the first move confers an advantage.

Resolution Phase:

Start with the most extreme score in any region. Whichever color wins the region causes the losing tiles
to switch color. Recalculate the score in the remaining regions.  Repeat until all regions have been

  • Sum the tile numbers of each color in each unresolved region, counting red as positive and black as negative.
  • Add 1/2 the value of  tiles in squares adjacenet to the each region, including diagonals.
  • The region (or regions) with the largest net value (red score - black score) is resolved, and awarded to the winner.
  • All the tiles belonging to the losing player in the region flip to the winner's color.  The flipped tiles now influence adjacent regions with the new color.
  • Repeat until all regions have been resolved.  The player owning the most regions wins.

Simplified Game:
In the simplified game, simply sum the tiles in each region and award the region to the winning
player.  There is no influence across regions, and no chained resolution.


A completed game, with the initial influence sums.  The largest score differential is in the upper right, so it is resolved first.
completed game
The red tiles in the upper right become black, and the influence for the remaining regions are recalculated.
step 1
The highest remaining region score is the upper left.   Red tiles in the upper left become black,  influence in the remaining regions is recalculated
step 2
The next region is the top-center.  Continue as before.
step 3
Resolving regions step 4-7
step 4 step 5 step 6 step 7
The final result, black controls 5 regions, red 4

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