Help for the Game of Ndengrod

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

  ndengrod challenge [-size=number] [-length=number] userid1 userid2

starts a new game for two 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 5).


Ndengrod is an abstract strategy game for two players who strive to make a line of 5 pieces of their colour.


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

After each move, all same-coloured groups that are surrounded (i.e. no member is adjacent to an empty cell) are captured and removed from the board. Surrounded enemy groups are captured first then surrounded friendly groups; pieces may not commit suicide but may create their own freedom.

A player wins by making a line of 5 or more pieces of their colour.

The following example shows a game won by X who has formed a line of 5 '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 . x . .   
   g-  . . x . o x .     
    h-  . . . . . .      
     i-  . . . . .      

First move equaliser: The second player has the option of swapping colours in lieu of making the second move. This stops the first player from making too strong (i.e. central) an opening move.


It may at first appear difficult to form 5-in-a-row on such a small board; 5-in-a-row games like Gomoku and Renju are typically played on much larger boards. However, the fact that surrounded pieces are captured means that at least one player's blocking pieces will eventually be captured, opening up the board for further line development.

It is generally good to keep all of your pieces in a single connected group if possible. Stray pieces isolated from any supporting groups are easier to capture, and the player who makes the first capture will generally win the game.

The central cell is the strongest as it has the greatest number of potential lines of 5 running through it.

A good strategy is to force the opponent into placing isloated pieces that can be cut off and captured. Such forcing moves may be achieved by making a line of 4 or an open-ended line of 3 that threatens to form an unbeatable open-ended line of 4.


The move syntax is:

  ndengrod move board# userid password d3   - place a piece at d3
  ndengrod move board# userid password swap - swap option (second move only)


Ndengrod rules by Ludi by Cameron Browne and copyright (c) Cyberite Ltd, 2008.

Ndengrod 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 these to determine whether they actually constitute viable games and, if so, how likely they are to be of interest to human players. The original rules specify that the game be played on a trapezoidal board, however changing the board shape to the more familiar and symmetrical hexagonal shape should not significantly affect play.

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

Implementation and Help file by Cameron Browne, August 2008.