Kentobori

Kentobori is the specific craft of carving registration marks into woodblocks. While kento refers to the registration system itself, kentobori is the act of cutting these marks with exacting precision. The carver must reproduce identical kagi (L-shaped corner mark) and hikitsuke (straight edge mark) on every block in a color set, ensuring that paper placed against any block sits in exactly the same position.

The accuracy required is remarkable — misalignment of even a fraction of a millimeter becomes visible as color misregistration in the finished print. The carver uses specialized chisels to cut the kento marks, working to tolerances that would challenge modern machining. In a print requiring twenty color blocks, all twenty must have perfectly matched registration marks.

Kentobori is one of the first skills a carving apprentice must master, and the quality of a workshop's kento cutting was a point of professional pride. Poor registration was immediately visible and reflected badly on both carver and printer. In shin-hanga production, master carvers like those employed by Watanabe Shozaburo were celebrated for their ability to produce flawless registration across highly complex multi-block prints.