This is an interesting variant of Frog Finder, created by Michael Coan in 2007. Since the basic rules are identical to Frog Finder, we only describe the important differences:
There are no red and blue frogs which would belong to the players. Instead, the game board always contains randomly positioned 9 green frogs which are invisible to both players. The object is to get more points than the opponent, gained by shooting and guessing until all 9 frogs are revealed.
The board size is 13x13 and always starts with 0 (a zero) in the very center of it. The purpose of this change is to avoid losing points at the first move when a shot is made with no information about the frog locations. It also means that the frogs are randomly placed at the board, except the central square G7 and all its surrounding squares.
Since the game ends when all 9 frogs are found (or shot), no further points are added/subtracted at the end because there are no frogs left to calculate.