1 A shell, especially mother-of-pearl, inlay technique commonly used for lacquer ware *maki-e 蒔絵. The shell was usually placed directly into the wood core by cutting through the ground and setting it flush with the wood's surface. The technique used pearl-like parts of such shells as ōmugai 鸚鵡貝 (pearly nautilus), yakōgai 夜光貝 (turban shell, lunica marmorata), awabigai 鮑 貝 (abalone) or aogai 青貝 (blue shell), chōgai 蝶貝 (pearl oyster), and shijimigai 蜆貝 (corbicula). Shells are worn down into several thickness on a whetstone or grinder and cut into shapes, then pasted or inlayed on a wood or lacquered surface, and polished. The thickest shell decoration, a thinner application, and the thinnest use of shell are called atsugai 厚貝, usugai 薄貝 and kenma 絹磨 respectively. Decoration with shells is also called kaisuri 貝摺. There are three ways of cutting shapes from shells: kirinukihō 切抜法 (cutting out), suitable for atsugai, is cut with a scroll saw and finished with a file or rubstone; uchinukihō 打抜法 (punching), for usugai, uses a punch with a template; and fushokuhō 腐食法 (eroding) which brushes patterns in lacquer on a surface of usugai paste, then applies hydrochloric acid so the unlacquered part is eaten away, before quickly washing it with water and peeling off the lacquer. Adhering shell to wood surface is achieved by: kannyūhō 嵌入法 (inlaying), where the shell sheet is inlaid in a carved surface; fuchakuhō 付着法 (adhering), where the cut-out shell is pasted on the wood and lacquered then polished; and oshikomihō 押込法 (pressing in), where the cut-out shell sheet is pressed into very thick lacquer.
The raden technique, introduced from Tang dynasty China to Nara period Japan, was used with *mokuga 木画 (mosaic), kohaku 琥珀 (amber) and taimai 玳瑁 (tortoise shell). Taimai, also called bekkō 鼈甲, was used from the Nara period. Taimaibari 玳瑁張り is a one kind of suki-e 透絵 (transparent painting) technique in which tortoise shell is covered over gold and silver foil and paint, and uses the *zōgan 象嵌 (inlay) technique together with raden. Raden techniques developed greatly in the second half of the Heian period and were applied to architecture in combination with maki-e. Through the Kamakura period, raden was often applied to saddles. In the Muromachi period, Chinese and Korean raden ware was highly valued, and Japanese raden was influenced by them. In the Momoyama period, it was adopted into Nanban art nanban bijutsu 南蛮美術 (see *nanban byōbu 南蛮屏風). Hon'ami Kōetsu 本阿弥光悦 (1558-1637) and Ogata Kōrin 尾形光琳 (1658-1716) used raden and maki-e techniques. Raden techniques were also used for *inrō 印籠 (seal case), combs and scabbards. Famous raden craftsmen include Ikushima Tōshichi 生島藤七 in the early Edo period, Aogai Chōbei 青貝長兵衛 and Somada zaiku 杣田細工 in the mid-Edo period, and Shibayama zaiku 芝山細工 in the late Edo period.
2 The technique originated in the Near East and its use eventually was imported to Japan from China in the 8th century. Many early examples are to be found in the *Shōsōin 正倉院 in Nara. During and after the Heian period, raden was frequently combined with *maki-e 蒔絵 lacquer techniques. Buddhist dais *shumidan 須弥壇, can be seen in the Byōdōin *Hōōdō 平等院鳳凰堂 and Taimadera *Mandaradō 当麻寺曼荼羅堂.