The Lines & Disengages
The lines are a simple way to describe which side of the sword you are attacking or defending. You can think of your inside as where your insides are (your stomach), and you can think of your outside as your outer parts (your back). Or the inside is where your offhand is. The same goes for your opponent. So, if you attack their inside, you are attacking towards the front of their body, but it is always in relation to which side of the sword you are on. If they parry, they will quite likely use the inside parry, which is why it is called as such.

Disengages are how we move quickly from one side of the opponent’s blade to the other or change line. This is done by lifting the tip of your sword over or under theirs. Typically followed by a rotation of the front edge to bring that edge and guard to oppose against their blade. Disengaging over is usually done when initiated cuts, whereas disengaging under is using done to initiate thrusts or to change line when using very point forward guards. The disengage should be done from the wrist. Keep the sword hilt in place and merely manipulate the height of the tip of your sword with your wrist to make it quick.
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