A Foundation of Fossilized Algae
The exceptional durability of Wajima-nuri (輪島塗), a traditional lacquerware from Japan's Noto Peninsula, has a surprising geological origin. The secret lies in a powdered undercoat material called jinoko (地の粉), which translates to "earth powder". This is earth; it is high-quality diatomaceous earth, a sedimentary rock composed of the fossilized remains of single-celled algae called diatoms. This material is found locally and is a feature of the Wajima-nuri technique.
The process of creating Wajima-nuri is extensive, sometimes involving over 124 distinct steps performed by specialized artisans. An important stage is the application of multiple undercoats of raw urushi lacquer mixed with the powdered jinoko. The microscopic, porous structures of the diatom fossils absorb the lacquer, creating a reinforced matrix that significantly increases the hardness and longevity of the finished object. This unique substrate makes the lacquerware remarkably resistant to damage. This technique of using a diatomaceous earth undercoat is a primary reason Wajima-nuri pieces are known to last for over 100 years.
From Miocene Seabed to Prized Tableware
The diatomaceous earth deposits in the Noto Peninsula are a direct result of ancient plankton blooms. During the Miocene and Pliocene epochs, this region was a marine environment conducive to massive populations of diatoms. Over millions of years, the silica-based skeletons of these microscopic organisms, called frustules, accumulated on the seabed, eventually forming the thick deposits of diatomite that are mined today.
The use of this fossilized plankton in lacquerware dates back centuries. Archaeological excavations in the Wajima area have uncovered lacquerware fragments from the Muromachi Period (1336–1573) that contain this local diatomaceous earth in their undercoating. The oldest surviving example of Wajima-nuri is believed to be a vermilion door from Juzo Shrine, made in 1524. The established techniques still in use today were refined during the Edo period (1603-1868). The combination of this unique geological material with the natural polymer of urushi lacquer is a use of local resources, perfected over hundreds of years of craftsmanship.