Adze Blade

A long, slender, rectangular adze blade (koʻi) made of stone. The blade is curved sharply, with the butt end smaller than the blade end, and chipped. The blade is smooth near the cutting edge.

Hawaiian adzes (koʻi) were essential woodworking tools in pre-contact Hawaiʻi, central to house construction, canoe building, and fine carving. Adze blades were primarily made from dense, fine-grained basalt or compact volcanic lava. Blades were shaped through systematic flaking with hammerstones and then ground smooth using stone slabs with sand and water; smaller adzes were occasionally fashioned from shell for lighter tasks. Metal, primarily iron, could be used for the blade post-European contact. Koʻi varied in size and form, including narrow, thick blades suited for deep cutting and broader, thinner blades designed for smoothing, with cutting angles adjusted to the hardness of specific woods. The blades were hafted to wooden handles (ʻau) using coconut fiber or ʻolonā cord lashings. If dulled significantly or broken, the blades could be replaced.