Here’s a little drill we do sometimes at Delaware Systema – limiting our range of movement. This was filmed a few years ago, but we still look at this drill every once in a while. The drill helps develop our understanding on how the body can move when we put limitations on it. In this case, not leaving the square.
Staying on the square allows for movement to be adaptable. This can be done with sticks, fists, kicks, or in this case shown below, with a knife.