Rules

Some attacks may only be performed From Behind. Such an attack must be performed when physically behind the opponent; you cannot reach around from the front. The attack must strike the opponent’s back half; this includes any part of the target, limbs included, which is more towards their rear than their front. If you can see both of your opponent's shoulder blades, you are probably behind them. From Behind type attacks made with ranged Weapons can be made from any direction and still count.