| What is Raden (mother-of-pearl inlay)? |
In raden tehnique, parts of shining shells such as abalone, nautilus shells, and white butterfly shells. "螺" refers to spiral shells, and "鈿" means inlaying.
It is a technique that came from the Chinese mainland about 1300 years ago and can also be seen in the treasures of Shosoin. Shells used in raden are categorized into thick shells and thin shells based on their thickness. Thin shells, called aogai in Japanese, are produced by thinning shells with a whetstone or boiling them to peel them thinly, with a thickness of less than 0.1 mm. There is also a technique called urasaishoku, where colors like gold or silver are applied to the back of the shell. Thick shells are shells flattened with a whetstone, with a thickness of about 1 mm.

| Making Process of Raden |
〈Using Thick Shells〉
① Cut the shells with a thread saw
② Carve patterns on the finished surface
③ Fit the shells into the carved parts
④ Apply Maki-e (sprinkled gold) and finish by polishing

〈Using Thin Shells〉
① Cut the shells with a knife
② Apply urushi to the back of the shells and adhere them
③ Apply urushi on top of the shells and polish them out
④ Apply Maki-e (sprinkled gold) and finish by polishing

<Source: "What is Traditional Kōgei?" Edited by Japan Kōgei Association East Japan Branch / Published by Unsodo, P.33>