Help For the Game Of Visavis

Introduction

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

    visavis challenge [-size=n] userid1 userid2

Starts a new game between userid1 and userid2 of the specified board size (range 5..25, default 25).

Rules

Two players, X and O, take turns placing a bridge between any two of their adjacent pegs not blocked by an existing bridge. The first player to complete a connected chain of bridges between their sides wins. Ties are not possible.

For instance, X has placed a bridge between the two 'x' pegs C5 and E3 in the following example. This move blocks O from playing a bridge between the two 'o' pegs at C4 and E4.

         X

   A B C D E F G H I
  1    x   x   x   x  1
   2 o   o   o   o   o 2
    3    x   x   x   x  3  
  O  4 o   o/  o   o   o 4  O
      5    x   x   x   x  5
       6 o   o   o   o   o 6 
        7    x   x   x   x  7  
          A B C D E F G H I  

                    X

The next example shows a game won by X, who has completed a continuous chain of 'x' bridges from the top edge to the bottom edge.

                       X

  x   x   x   x   x   x   x   x   x   x   x   x
o   o   o   o   o   o  \o   o   o   o   o   o   o
    x   x   x   x   x   x   x---x---x   x   x   x
  o   o   o   o   o   o  \o/  o   o  \o   o   o   o
      x   x   x   x   x   x   x   x   x   x   x   x
    o   o   o   o   o   o   o   o   o/  o   o   o   o
        x   x   x   x   x   x   x   x   x   x   x   x
      o   o   o   o   o   o/ \o   o/  o   o   o   o   o
          x   x   x   x\  x   x---x   x   x   x   x   x
        o   o   o   o   o  \o   o   o   o   o   o   o   o
            x   x   x  /x   x   x   x  /x\  x   x   x   x
          o   o   o---o   o/  o   o---o   o---o---o   o   o
      O       x  /x   x   x   x   x   x   x   x   x\  x   x     O
            o---o---o   o  \o   o   o   o   o   o   o   o   o
                x   x\  x   x   x   x   x---x   x   x\  x  /x
              o   o   o---o  \o   o   o/  o  \o   o   o   o   o
                  x   x   x\  x---x---x  /x\  x   x   x\ /x   x
                o   o   o   o---o   o---o   o  \o   o---o   o   o
                    x   x   x   x\ /x   x   x   x  /x   x   x   x
                  o   o   o   o   o   o   o   o/  o   o   o   o   o
                      x   x   x   x   x   x---x   x\  x   x   x   x
                    o   o   o   o   o   o  \o   o---o   o   o   o   o
                        x   x   x   x   x   x   x   x   x   x   x   x
                      o   o   o   o   o   o/  o   o   o   o   o   o  o
                          x   x   x   x   x   x   x   x   x   x   x  x

                                                 X

Notes

Visavis is a Shannon switching game on the edges and belongs to the same class of connection games as Bridg-It and TwixT (and to some extend Trellis). Even though a trivial winning strategy has been found for Bridg-It (called Connexxions on the server) Visavis consists of a more complex system of overlaid triangular grids that allows richer variety of play, and no winning strategy is known.

Michail Antonow points out that different tactics must be applied when blocking an opponent's rightward path as opposed to a leftward path. The path can be abruptly cut by a single piece in one direction only; in the opposite direction a single bridge will only divert the path and two bridges are needed for a successful block.

The rules state that a bridge can be placed between any two adjacent pegs of the same colour. However since it can never help to place a bridge between the opponent's pegs, then it is assumed that all moves are made between the current player's pegs. This also simplifies the board notation.

The original rules only provide 120 bridges (60 per player). After the 120th move players would have to scavenge an existing bridge of theirs from the board and play it elsewhere. This feature has not been implemented.

Syntax

Horz (O) moves first. The move syntax is:    

    visavis move board# userid password coord

where "coord" specifies an empty and unblocked bridge position between two of the current player's pegs (eg F4) not the pegs themselves.

References and History

Visavis was invented by Michail Antonow in 1995 and copyrighted in 1996. It was originally called Nexus.

Implementation and help file by Cameron Browne, December 2003.