How does the angle of the heel change during a back stance to maximize stability and mobility?

In Kokutsu Dachi (Back Stance), the heel of the front foot is typically angled inward, while the heel of the back foot is positioned directly behind the front foot. This specific heel angle maximizes stability and mobility by influencing the base of support and facilitating quick transitions. The slight inward angle of the front heel prevents the front knee from collapsing inward, which enhances knee joint stability and allows for efficient weight transfer. The rear heel being directly behind the front foot, and in line with it, ensures that the weight distribution is biased towards the rear leg (approximately 70% of the weight is on the rear leg), which is essential for generating power and maintaining balance. A straight line heel-to-heel alignment also makes it easier to move either forward or backward. By strategically positioning both heels, the back stance achieves a balance between a solid defensive posture and the ability to move quickly in response to an opponent's movements.