What kenchi-ishi means
Kenchi-ishi is stone dressed for walls, retaining walls and bridge abutments, with a squared face and a body tapering toward the back. From the front it looks square, and from the side it narrows into the wall like a truncated pyramid. The depth is called the hikae, and standards such as Nagoya City's rules for retaining walls require it to be at least a set length.
Being uniform in size and shape, the stones can be laid in level courses, Nunozumi, or set diagonally, Tanizumi. The Ministry of Land, Infrastructure, Transport and Tourism's guide to stone structures for rivers shows kenchi-ishi used in level, diagonal and random coursing and names the parts of the stone, such as the face and the hikae. They are used both in mortared work, Nerizumi, and in dry walling, Karazumi. In the modern period they were used in great quantities for river revetments, railway and road retaining walls and bridge abutments, and concrete kenchi blocks later became common.
Reading the records and the structure
Records combine the stone form with the coursing, as kenchi-ishi in level courses or in diagonal courses. The Wakasa River Bridge of the Wakasa Railway in Wakasa, Tottori, a single-span deck steel girder bridge 9.1 metres long, is recorded with abutments finely faced in granite kenchi-ishi laid in level courses; the stone and its laying form part of the bridge's value.
On site, look for square faces of uniform size with regular joints. The neatness of the faces distinguishes them from walls of natural or split stone, and concrete kenchi blocks can be told apart by their uniform surface without grain.
References
- 若桜鉄道若桜川橋梁｜国指定文化財等データベース（文化庁）
- https://kunishitei.bunka.go.jp/bsys/maindetails/101/00007295
- 河川の景観形成に資する石積み構造物の整備に関する資料｜国土交通省
- https://www.mlit.go.jp/river/shishin_guideline/kankyo/stone-structure/s-1.pdf
- 宅地造成等の手引（練積み造擁壁）｜名古屋市
- https://www.city.nagoya.jp/jutakutoshi/cmsfiles/contents/0000009/9347/R04.4.C.pdf
Last verified: 2026.09.26