Katana Info Katana Guides & Knowledge Hub » hasaki

The hasaki is the very edge of a katana—the fine cutting surface responsible for the sword's remarkable sharpness and cutting ability. While often confused with the broader ha (cutting edge), the hasaki refers specifically to the sharpened portion that makes contact during a cut. This guide explains the anatomy of the katana's edge, how the hasaki is formed during polishing, and why its geometry...