A sculpture technique used to carve a large hollow space *uchiguri 内刳 inside a statue that was originally one piece of wood *ichiboku-zukuri 一木造. This hollowing prevents both the wood body from cracking with changing moisture levels and lessens the weight.
Typically, warihagi involves three steps: 1) dividing the roughly carved block of wood in half with a chisel *nomi 鑿; 2) carving out a hollow in each piece; and 3) refitting the halves together. This technique makes it easier to carve a sufficient hollow and eliminates the need (because the two halves join naturally and tightly) for polishing of joint surfaces or for a wood cover to hide a hole into the interior which other hollowing techniques require. When the main body of a statue is made by this technique, the statue can be categorized both as "single-block with attached appendages" ichibokushiki yoseki-zukuri 一木式寄木造 or simply warihagi-zukuri 割矧造.
The warihagi technique can be seen in many yearly Buddhist images of the 8th-9th century, such as Yakushi Nyorai-zō 薬師如来像 of Shin'yakushiji 新薬師寺, Nara. It continued to be used through succeeding periods as one of the two main techniques of Japanese wood sculpture. After the 11th century, with the diffusion of the other major techniques *yoseki-zukuri 寄木造, technical variations, such as *warikubi 割首, warite 割手, and wariashi 割足 (where minor sculptural parts such as the head, hands or feet were hollowed out) were developed from the basic technique of warihagi.