Virus Wars is a two-player board game that simulates an evolution of two colonies of viruses, which are growing and absorbing (zombifying) each other. The exact origin of the game is unknown but it was actively played as a paper-and-pencil game in Saint Petersburg State University in 80s. There were several variants of the game with slightly different rules.

• Board and pieces
• Objective
• Play
• External Links

Virus Wars can be played on a recrangular grid of any size.  igGameCenter uses 11x11, 13x13 and 15x15 boards.

Two players play with special pieces, which are Blue and Red viruses:        

Additional pieces ("zombies") are used in the game to designate opponent's pieces, which are "zombified" by a player:     

The game begins with an empty board.

Both players have an unlimited number of viruses of their color: Blue and Red.

Starting with Blue, players take turns making 5 steps per turn. Each step can be either generation or absorption:

• generation includes putting a new virus of player's color on any "accessible" (see below) empty square of the board;
• absorption includes zombifying one of opponent's viruses on any "accessible" (see below) square of the board, i.e. replacing an opponent's virus with a special "zombie" piece of player's color. "Zombies" remain permanent till the end of the game, i.e. they cannot be "revived", "reclaimed" or removed from the board.

A square is "accessible" in the following cases:

• the "square" is vertically, horizontally or diagonally adjacent to a player's virus already on the board (even if that virus was placed as one of the previous steps during the same turn);
• the "square" is connected to a player's virus already on the board through a chain of horizontally, vertically or diagonally connected "zombies" of player's color (even if those "zombies" appeared as one of the previous steps during the same turn).

Below is the example of one move:

On this illustration all "accessible" squares for the Blue player are marked with blue dots. Please note that squares around the two blue "zombies" at the bottom are not "accessible" because they are not connected to any "live" blue virus.	Blue player makes his first step and puts his virus on one of the "accessible" squares.
The newly placed blue "virus" adds 5 new "accessible" squares. Now the two red viruses can be "zombified".	The Blue player makes 2nd and 3rd steps, "zombifying" two red viruses.
Zombifyng two red viruses on the right made it possible to "access" another red virus on the bottom.	The Blue player makes the 4th step, "zombifying" one red virus at the bottom.
Now the other red virus at the bottom is also "accessible".	The Blue player completes the move with the 5th step, "zombifying" the other red virus at the bottom.

At the beginning of the game the board is empty and there are no "accessible" squares so the Blue player can put his first virus on any square on the left edge of the board and the Red player can put his first virus on any square on the right edge of the board.

A player must do all 5 steps per his turn. If a player is unable to do all 5 steps then the player loses the game.

• "Virus Wars" rules and history on Wikipedia (rus).