Taking down from behind is lot easier than taking them down from in front: Taking a skilled down from neutral positions is never easy and often gets strongly countered. Getting behind them and then taking them down is usually considerably easier and the generally less problematic ( though of course Garry Tonon proved an exception to the rule by countering directly into a match winning lock!) moves that get you behind an opponent are thus highly valued in Jiu Jitsu – duck unders, slide bys, throw bys, arm drags etc are all excellent methods of getting behind a standing opponent and making your job of taking them down into controlling positions on the mat much easier and safer. Make sure you make a concerted effort to slip behind opponents at all times in standing position. Even if you don't succeed it often open doors to more conventional frontal takedowns and if you do succeed, you'll make your job a lot easier and less risky