Help For Oust

Introduction

Welcome to the network Oust server. The rules of Oust are below. The Oust challenge command and swap command are described here. Other commands are the same for all pbmserv games.

Current games can be viewed here.

Challenge Command

oust challenge [ -size=N ] userid1 userid2: Start a new game between userid1 and userid2.
Default board size is 19x19.

Swap Command

oust move [board#] userid password swap: Player #2 claims Player #1's first move as his own, swapping turns.

Oust Rules

AUTHOR'S NOTE: Feel free to distribute this document.

Introduction

Oust is played with a Go set. The board starts out empty. Each player takes ownership of an entire set of like-colored stones. Players take turns adding their own stones to the board. Draws and ties cannot occur in Oust. Mark Steere designed Oust in July, 2007.

Stone Placement

You initiate your turn by adding a single stone to an unoccupied point. If you have a placement available on your turn you must make one. If you don't have any placements available you must pass your turn. There will always be a move available to at least one of the two players. A "connection" will denote a horizontal or vertical adjacency here.

Non-Capturing Placements

When you make a placement which does not form any connections with your own stones, you have made a non-capturing placement. So a noncapturing placement either forms no connections with any stones, or forms one or more connections only with enemy stones. Making such a placement concludes your turn. In Figure 1 the only placements available to Black (#) are non-capturing placements and are indicated by ?'s.


                            # . ? O ?
                            . # . ? O
                            # . ? ? ?
                            . ? O ? .
                            ? O ? . #

            Figure 1 -- Available placements for Black (#).

Capturing Placements

A "group" here can be a singleton (a single stone which is not connected to any other like-colored stones), or a set of two or more interconnected, like-colored stones. A group includes all of the like-colored stones connected to it.

When you place a stone which forms one or more connections with your own groups, you create a new, larger group of at least two of your own stones. You can only make such a placement if said new group will have one or more connections with enemy groups upon its creation and if all said enemy groups are smaller than said new group. In this case all said enemy groups are removed from the board.

After capturing one or more enemy groups and while it is still your turn, you must continue to add stones during your turn until you make a non-capturing placement, at which time your turn is concluded.

In Figure 2, Black's newly formed group of two captures the three white singletons.


                            . . . O O
                            . O . . .
                            # ? O . .
                            . O . . .
                            . . . . .

            Figure 2 -- Black plays at ?, capturing 3 white singletons.

In Figure 3, Black captures the four white singletons connected to his newly formed group.


                            . O . O .
                            O # . # .
                            . # # ? #
                            O . . . #
                            # # . O #

            Figure 3 -- Black plays at ?, capturing 4 singletons.

In Figure 4, Black's newly formed group of seven captures White's group of six.


                            O O O O O
                            O . . ? .
                            # . . # .
                            O . . # #
                            . . # # #

            Figure 4 -- Black captures connected group.

In Figure 5, it is Black's turn. He has no placements available and so must pass his turn.


                            O O O O O 
                            O O O O .
                            . O . . #
                            # . # # #
                            # # # . #

            Figure 5 -- Black must pass.

In Figure 6, Black captures all of the white stones and wins the game.


                            O . . . O
                            O O # O O
                            O . ? . O
                            O . # . .
                            . # # # O

            Figure 6 -- Black plays at ? to win.

Object of the Game

If you make a placement which captures all of the enemy stones on the board you win.

Example Position

Figure 7 shows a position from an actual game played at Gamerz Net. The size of the largest group and the total number of stones are shown for each player. rrognlie's largest group consists of 41 stones and he has a total of 46 stones on the board.


    x: rrognlie        41/46
    o: marksteere      20/40

      A B C D E F G H J K L M N 

  13  o . . . o . . o . . o . .  13
  12  o o o o . o o . o o o o o  12
  11  . o . o . . . o . . o . o  11
  10  . . o o o . , o o , . . o  10
   9  x . . o o o o o . o . . o   9
   8  . . . . o . o . . . o o o   8
   7  x x x , . o , . x , . o .   7
   6  . . x . . X . x . x . . .   6
   5  x x x x x . . x x . x . x   5
   4  x . x , . x , . x x x x x   4
   3  . . x . x . . x x . x . .   3
   2  . . x x x x x x x x x x x   2
   1  x x x . . . . . x . . . .   1

      A B C D E F G H J K L M N 

            Figure 7 -- Example position