Sangaku Geometry Puzzles

Elegant circle-and-polygon problems from Edo-era tablets: place, resize or measure shapes so tangent circles and areas match a target.

Heritage note

Part of the living heritage of Japan. Some forms of this practice carry deep meaning for the communities who keep it; here we describe the play and the craft only, with respect for its roots.

Origins

Usually placed in the era of Age of Contact and Craft (about 1500 to 1800), although its exact origins are uncertain, within the cultural world of Japan and Korea.