Abalone game

Abalone is a two-player strategy game which can be quaintly summarized as "sumo wrestling with marbles". The board consists of 61 circles arranged in a hexagon five on a side. Each player has fourteen marbles which rest in the circles, and are initially arrayed as shown below.

 Initial Position

The player with the black marbles always moves first. The marbles are moved in lines of one, two, or three, either inline or broadside.

 Black opens with a broadside move

 White counters with an inline move

When one player has numerical superiority in a line (three to two, three to one, or two to one) he may push the opposing marbles with an inline move. Broadside pushes are not allowed. The diagrams below illustrate three black pushes. The objective is to push six opposing marbles off the edges of the board.

Before black push	After black push

The diagram below illustrates several situations in which it is impossible for black to push. In the top line black does not have numerical superiority. In the middle line, black has four marbles to three, but a maximum of three marbles may be moved each turn, so again no push is possible. In the bottom line black cannot push because it is forbidden to dislodge one's own marbles.

Black has no available pushes

The notation for recording moves gives the letters A-I to the horizontal lines, and the numbers 1-9 to northwest-southeast diagonals.

      I O O O O O
     H O O O O O O
    G + + O O O + +
   F + + + + + + + +
  E + + + + + + + + +
   D + + + + + + + + 9
    C + + @ @ @ + + 8
     B @ @ @ @ @ @ 7
      A @ @ @ @ @ 6
         1 2 3 4 5

An inline move can be denoted by the movement of the trailing marble. Notation for broadside moves is not entirely standardized.

The rules can be mastered in a minute or two, and the flow of the game is fast-paced. Abalone tends to draw in new players much more quickly than complicated, slow games such as chess. Also, pushing the marbles is physically satisfying. The click-click-click as one's line of marbles pushes the enemy back is almost musical.

Here are some moves from a sample midgame. No marbles have yet been ejected in the diagrammed position:

1. F5-E5 : Black disrupts two white lines

1... C4-B3* : White pushes a black marble off the board.

2. C2-B2* : Black pushes a white marble off the board.

Unfortunately, the dynamics of the basic game have one serious flaw: a good, conservative player can set up his marbles in a defensive wedge, and ward off all attacks indefinitely. An attacker may try to outflank this wedge, or lure it into traps, but such advances are more dangerous to the attacker than the defender.

 Black can defend forever

There are several solutions to this conundrum. First, in tournaments, a judge may penalize a player for playing defensively. This solution is somewhat unsatisfactory, given that a judge may not always be present, and that "defensive play" is a subjective notion.

Second, several variations of the rules of play have been developed for the same board and marbles. Unfortunately, none of the variations has the same appealing simplicity of the original.

Third, and perhaps best, alternative starting positions have been designed to make the formation of stalemate wedges less likely. Experiments are still underway to find an opening position which neither devolves into a draw, nor gives too great an advantage to the first player. One popular attempt is the marguerite position displayed below.

 Marguerite starting position

The complete rules, strategy hints, and on-line play are available in English, French, and German at http://www.abalonegames.com/