The Circle
The round shield is the first shield of most fighters, and the shape they graduate from least. It is the shape of a circle — the same distance from the hand to every edge — and that is the whole argument: the fighter does not have to aim it. The blow comes from anywhere, and the shield is already where the blow is.
A common round shield is an oak face, a rim of iron, a grip that fits one hand and no more. It is the shield of the militia, of the farm hand who has not forgotten the fight, of the guard who stands at the gate and has been standing at the gate for twenty years. A master round shield has the iron rim doubled, and a maker's mark under the leather. The masterwork does not exist much. The round shield is not a shape people keep working on. The round shield is a shape people finish.
In the Hand
The round shield is the first stance, made oak: brace. It covers the hand to the knee, and the fighter behind it takes the blunt wound into the arm instead of the body. It is not a wall. It is a circle that refuses to be anywhere the blow wants to be, and the fighter who learns the circle learns the rest of the fight around it.
"A round shield is a promise with no corners. The corners are where the promises break." — Tigole