Well, for your first shot (assuming you go first), the odd of guessing a frog is about 5.6%, assuming you won't guess one of the middle 9 squares, as they will be empty. The board is 13x13, making 169 squares; the middle 9 are empty, so 9 frogs will be found on 160 squares, or about 5.6% of the squares.
Running a simulation where both players guess randomly (but won't guess a square that was guessed before; and won't guess one of the middle 9 squares) shows the game is pretty even, and lasts about 144 half-moves.
(Cacher) Lorsque vous jouez un coup dans une partie, vous pouvez décider quelle autre sera affichée en suivant en choisissant l'option appropriée dans la liste des 'aller à'. (pauloaguia) (Montrer toutes les astuces)