Copyright (c) 1976 David Wells

The game is played on an empty 7 by 12 hexagonal board.

GROUP - A set of connected stones.
TURN - In their turn each player:
Grows each group of less than five stones, by adding a new stone on an adjacent cell, however, the new added stones must not be adjacent to enemy ones, or to friendly stones from another group. This is mandatory, while there is valid moves.
Starts a new group by placing a stone on an empty cell. This is mandatory, while there is valid moves.
Moves any groups that they want to move (see below).
Attacks any enemy stones (see below).
However, the player can choose to pass his turn.
There is a rule to balance the advantage of first move: White's first move must not be further than four lines from the edge of the board.
GROUP MOVE - A group moves by using as many single-stones "jumps" as there are stones in the group. A jump consists of moving a stone over a straight line of stones of the same group to the intersection on the far side. 
A stone cannot jump to an intersection adjacent to another friendly group.
The jumps can be divided among the members of the group anyway the player likes, so a stone may jump more than once or not at all. 
If the group ends up split as a result of moving, it loses all but the largest part of the group (if they are equal, the player chooses). However, the group may be reformed during that moving stage without any loss.
A player may not have to use a group's full quota of jumps.
A player has to finish moving an entire group before moving another one - he can't partly move one group, move another, then come back to moving the first group again.
GROUP ATTACK - The "strength" of a stone is the number of adjacent stones in its own group which are directly adjacent to it. After all of one side's moves have been made, any stone which is stronger than an adjacent enemy stone kills that enemy stone, which is removed from the board. 
Each stone may only kill once per turn. 
Killing is not optional, but the player makes his kills in any order he wishes.
Stones do not have to move in order to kill.
The strength is calculated after the moves are over, and all captures are considered to be simultaneous.
If the size of the groups involved in a particular kill differs by more than one, the kill becomes a massacre (or "overkill"). 
Place a red counter on the intersection that was occupied by the killed stone (this stone is removed and delivered to the player that owns it). The point occupied by the counter can not be used for the rest of the game.
To reiterate an important point: the strength of a stone is the number of stones it is adjacent to in its group, but whether its kills become massacres depends on the size of the whole group.
GOAL - The game ends when both players agree to do so, then the score is calculated as follows:
Each player counts one point for every intersection they occupy, and one point for every empty intersection adjacent to one of their stones but not adjacent to an enemy stone. Red counters do not count as empty intersections. The player with the higher score wins!

Placing the first soldiers

The first stones try to create zones of influence. On the second move, the players grow their initial K8 and I10 stones. 

I wish to thank John Lawson for detailed information about Guerilla. Luding has some limited information about Guerilla. Another page dealing with this game is, but it seems that it is down.