Tobikanna 飛び鉋

Tobikanna (chatter marking) is a decorative technique in which a springy metal blade is held against a piece as it turns on the potter's wheel, skipping across the surface to cut a rhythmic band of small chisel marks. It is a signature technique of Onta ware in Oita Prefecture, associated with the mingei (folk craft) tradition.

The grooves create variations in glaze depth, producing lighter and darker shades where the glaze pools differently. On celadon pieces, the technique allows one to see both the lighter glare of the glaze and the darker tones formed within the grooves.