組み立ての要点
Ita Tsugi is often the first joint a student learns. By carefully planing mating edges square and true, two boards can be joined seamlessly without visible gaps. This technique forms the foundation for understanding grain direction and wood movement. Mastering Ita Tsugi teaches the kanna (plane) control that underpins nearly every other Japanese joinery skill.
歴史的背景
Ita Tsugi (board splicing) predates complex frame joinery in Japanese carpentry. Before students cut mortises or scarfs, they learn to create invisible edge joints for table tops, panel doors, and wide boards. The emphasis on long-grain contact and proper clamping technique mirrors Kiritsuke Tsugi at a simpler scale. Traditional workshops treat a flawless Ita Tsugi as proof that a student understands grain, moisture, and plane setup.
組み立て手順
- Select boards with compatible grain direction and moisture content.
- Plane one mating edge straight and square using a marking gauge and kanna.
- Plane the second edge to match; hold the boards together and check for gaps with backlight.
- Apply adhesive along the full length; clamp evenly to prevent bowing.
- Plane the assembled panel flat once the glue has cured.
日本で見られる場所
- Traditional furniture and panel doors — Throughout Japan — table tops and fusuma panels
- Woodworking schools — Suikoushya (Kyoto), Hambara Miyadaiku workshops
バリエーション
Butterfly keys (Watari-ago in repair contexts) can reinforce wide panels. Some craftsmen use splined edges for extra alignment. For visible panels, book-matched grain is preferred over random edge joints.
用途
- Table tops
- Panel construction
- Wide boards
必要な道具
- Kanna plane
- Marking gauge
- Clamps