In most team sports you can do a lot of damage from the flanks. As every amateur football, rugby or hockey coach knows, if you get your right or left wing player to keep wide, and get behind the defence, you can open up the opposition. It's exciting, exhilarating, and when it works, it's magic.

The same can be true in military battles – get down the sides and round the back of your enemy and you can take them apart.