Mentori: The Faceted Surfaces of Japanese Pottery

Mentori, faceting, is the technique of cutting away the surface of a formed piece to create flat planes. A piece as thrown has a circular cross-section; a blade taken to it turns that section polygonal.

The cutting happens while the piece is leather-hard. Too soft and the blade sinks; too dry and it chips. Judging that narrow window, the maker uses a trimming tool, a wire bow or sometimes a knife, cutting from top to bottom in a single pass.

The essence of faceting is that it decorates by subtraction, not addition. Nothing is added as in painting; the surface appears only through cutting. So a plane once cut cannot be restored. A single judgement that allows no second try becomes, directly, the expression of the piece.

Faceting against shinogi

Both are carved decoration, but the forms they produce differ.

What faceting gives a piece

• Changing light　Because each plane sits at a different angle, the same glaze reads bright on some faces and dark on others. Turning the piece changes its expression.
• Gradation in the glaze　Glaze runs thin over the cut corners and pools at the centres and boundaries of planes. Even a single glaze gains tonal range.
• Ease of holding　Flat planes and corners meet the fingers, so it slips less than a round piece. That is why sake cups and tea cups favour it.
• How food reads　A straight-edged outline tightens the composition of what is served.

Related terms and guides

Related terms

• Shinogi: The Carved Ridges on Japanese Pottery
• Kodai (Foot Ring): The Part Collectors Check First
• Rokuro: How a Pot Is Thrown on the Wheel
• Tatara-zukuri: Building Pottery from Clay Slabs
• Icchin: Slip Trailing, the Raised Dot Technique
• Japanese Pottery Glossary | Terms, Techniques & Kilns

Read further

• Five Decorating Techniques on Japanese Pottery
• How Japanese Pottery Is Shaped: Five Forming Methods
• Japanese Pottery Glazes: The Main Types Explained