Help for the Game of Yavalath

Welcome to the network Yavalath server. The challenge command is described here. Other commands are the same as for all pbmserv games.

  yavalath challenge [-size=number] [-length=number] [-no_auto] userid1 userid2 [userid3]

starts a new game for two or three players.

The -size parameter specifies the number of cells along each side of the board (default 5).
The -length parameter specifies the target line length (default 4). The forbidden line length will be one less than the target line length.
The -no_auto parameter turns off automatic blocking moves (on by default).


Yavalath is an abstract strategy game for two players. Players strive to make a line of 4 pieces of their colour, but lose if they make a line of 3 before doing so.


The board is initially empty. Players take turns placing a piece of their colour on an empty cell.

A player wins by making a line of 4 or more pieces of their colour, and loses by making a line of 3 without also achieving a line of 4 or more on the same move. The game is tied if the board fills up before either player wins or loses.

The following example shows a game lost by X, who has formed a line of 3 'x' pieces without also forming a line of 4 'x' pieces.

            1 2 3 4 5    
           / / / / / 6    
                    / 7  
     a-  . . . . .   / 8  
    b-  . . . . . .   / 9 
   c-  . . . x o . .   / 
  d-  . . x . x . . .    
 e-  . . o . o x . . .  
  f-  . . o o . . . .   
   g-  . . x . o x .     
    h-  . . . . . .      
     i-  . . . . .      

Three-Player Version

The three-player version is played according to the same rules, except that players must block the next player's win if possible, and any player forming a line of 3 without also forming a line of 4 is removed from the game (but not their pieces).

The winner is either:
1) The last surviving player, or
2) The first player to form a line of 4.

The two-player version is deadly due to the prevalence of forced move sequences. The three-player version is just evil :)


The move syntax is:

  yavalath move board# userid password d3

This command places a piece of the current player's colour at position d3.

Moves that block the next player from winning are made automatically, unless the the player has a winning move or the -no_auto option is specified.


Yavalath rules copyright (c) Ludi by Cameron Browne, November 2007.

Yavalath was designed by machine. The rules were created by a programme called Ludi that evolves rule sets from existing games into new combinations, then measures the resulting rule sets to determine whether they actually constitute viable games and, if so, how likely they are to be of interest to human players. The machine did not actually suggest the three-player version; this was a natural extrapolation of the two-player rules.

The name "Yavalath" was randomly created from a list of Tolkien-style word forms by a Markovian process.

Implementation and Help file by Cameron Browne, December 2007.