Grand Series Urushi

The Grand Series is where Kurono Tokyo stops being a watch brand and becomes something closer to a craft preservation project. Every Grand Series watch features a dial made from urushi lacquer, handcrafted by female artisans in Kyoto who inherited a technique introduced from Tang Dynasty China during the Nara Period, between 710 and 794 AD. That is not marketing language. It is a direct lineage of more than a thousand years, practiced today by a handful of master-level artisans. The Grand Series is my favorite expression of what Hajime Asaoka does with Kurono.

Urushi lacquer starts as sap from the Japanese lacquer tree, Toxicodendron vernicifluum. The trees must grow for 10 to 15 years before they produce enough sap to harvest. A tapper called a kakiko makes shallow horizontal incisions in the bark with a chisel-like tool, then returns every five days to scrape the accumulated sap into a container made from magnolia bark. A 20-centimeter diameter tree yields roughly 200 grams of sap over an entire season. The traditional Japanese practice is koroshi-kaki, the killing tap. Over five months, the tree is progressively tapped from bottom to top until every accessible area has been incised. Then the tree is cut down. New shoots emerge from the root system and reach tappable size in about ten years.

The active compound is urushiol, the same chemical family as poison ivy. Raw sap is roughly 65% urushiol, 25% water, and the rest is plant gum and a copper-containing enzyme called laccase. What makes urushi unlike any other finish on earth is that it does not cure by drying. It cures by absorbing moisture. The laccase enzyme uses oxygen and ambient humidity to trigger an oxidative polymerization reaction that cross-links the urushiol molecules into a thermoset polymer. Below 60% relative humidity, the reaction stops. The artisans cure each layer inside a muro, a wooden humidity cabinet, at 75 to 85% humidity and around 25 degrees Celsius. The result is a coating that resists water, dilute acids, alkalis, and temperatures up to 300 degrees. Archaeological evidence from the Kakinoshima site in Hokkaido dates urushi lacquerware to approximately 9,000 years ago, making it one of the oldest continuously practiced craft techniques in human history. The earliest finds are red-lacquered burial ornaments colored with bengara, iron oxide ground to a fine powder. Urushi predates the wheel, predates bronze, predates written language in Japan. The craft survived the Jomon, Yayoi, Nara, and Heian periods. By the Muromachi era, maki-e decoration with gold and silver powder had become an emblem of imperial culture. Regional schools developed their own traditions: Wajima-nuri in Ishikawa, Tsugaru-nuri in Aomori, Ryukyuan lacquer in Okinawa. All of them work with the same sap from the same tree.

The artisans apply many thin layers of highly refined urushi, waiting for each to cure before applying the next. The full process takes approximately two months per dial. After the final layer, the polishing begins. The technique is called roiro-nuri. They start with togisumi charcoal from crape myrtle wood, soft enough to abrade without scratching. Then a finer charcoal pass. Then a thin wipe of raw lacquer pressed in with cotton and immediately wiped off with crumpled rice paper. Then a polish with tonoko clay powder mixed with oil. The final stage uses deer horn powder on bare fingertips. The work is so delicate that even the slightest wisp on a fingertip can cause striations in the finish. If that happens, the entire dial has to be rebuilt from scratch. There is no fixing a striation. There is no sanding it out. The dial is ruined and the two months of work start over.

The Grand Akane was the first urushi dial Kurono produced. Akane means madder red, named for the natural dye extracted from the root of the madder plant. The dial features a hamon sword pattern, the wavy temper line visible on a Japanese katana blade, created through niiro chemical treatment under a suki-urushi topcoat. Niiro is a patination process used in traditional metalwork. Suki-urushi is the refined, translucent amber lacquer used for the final protective coat. The combination creates depth that changes with every angle. Two hundred pieces were made. Having held the Akane for extended periods, what stays with me is how the light dances across the surface. The red shifts from a warm burgundy in low light to a vivid crimson when sunlight hits it directly. It is alive in a way that no photograph can fully capture.

The Grand Hagane followed. Hagane means steel. The name comes from tamahagane, the rare steel used by traditional Japanese swordsmiths. Tama means round and precious. Asaoka's maternal grandfather ran ironworks, so the connection to traditional metalworking runs through his family. The Hagane dial is layered in gold and brown urushi tones that create a translucent mirror finishing. Under changing light, the colors shift between warm gold and deep brown. The old-style Kanji numerals are another deliberate touch. The character at seven o'clock is the Kanji for urushi itself. That was not an accident. Of all the urushi dials, the Akane and the Mori are the ones I find myself drawn to most. The orange warmth of the Akane and the deep forest green of the Mori have a quality that changes as the lacquer ages. Urushi develops its own patina over time. The layers deepen. The translucency shifts. A dial that looks one way in year one will look subtly different in year five. That is not a defect. That is the material doing what it has done for ten thousand years.

Grand Hagane: gold and brown urushi tones inspired by tamahagane steel

The 2022 Anniversary Grand Mori continued the urushi line. Mori means forest. The dial pattern mimics sun rays seeping through layers of tree canopy. The concept was that nature is the teacher. All three sold out in under an hour, with the Mori gone in twelve minutes. Production was limited to hundreds of pieces for each model, constrained not by marketing strategy but by the physical reality of how long each dial takes to produce. You cannot scale urushi. There is no factory shortcut. Either the artisan's fingertips produce a perfect finish or the dial goes in the trash.

Grand Mori: urushi dial mimicking sun rays through a forest canopy

Then came the Grand Urushi Aoyama trio, released in December 2022 to celebrate the opening of the Kurono salon in Kita-Aoyama, Tokyo. Three watches with urushi dials in green, red, and brown, each with subtle patterns applied under the top coat of lacquer. The dials are almost completely sterile, just the Kurono wordmark near twelve o'clock. No numerals, no indices, no date window. Pure urushi. You could only order and pick up the watches at the salon itself. No online ordering. No shipping. You had to physically go to 2-10-22 Kita-Aoyama, Minato, Tokyo, walk in, and buy them in person. Only 88 sets were produced. The presentation box was made from Japanese paulownia wood.

The Grand Urushi Aoyama trio on Japanese paulownia wood: red, green, and brown

The sap itself is dangerous to handle. Urushiol causes severe contact dermatitis in most people. It is the same compound responsible for the rash from poison ivy. Both plants belong to the genus Toxicodendron. The artisans who work with raw urushi have developed tolerance over years of repeated exposure. Even so, fresh sap on unprotected skin will produce blisters within hours. The fact that these dials exist at all is a function of human stubbornness and generational knowledge that refuses to die.

The Grand Mori on the wrist, green urushi catching the light

Every Grand Series watch uses the same 37mm polished 316L stainless steel case at 7mm thick with a box sapphire crystal and the Miyota 90S5 automatic movement. The specs are identical across the line because the specs are not the point. The dial is the point. Each one is a collaboration between Asaoka's design vision and Kyoto artisans whose craft predates every watch brand in Switzerland by centuries. That combination, at this level of execution, does not exist anywhere else in watchmaking. Monozukuri, the Japanese philosophy of making, holds that the spirit of the maker is inseparable from the object. Every Grand Series dial carries the fingerprints, literally, of the artisan who polished it. That is not a metaphor. The roiro-nuri technique requires bare fingertips on the surface. The craft enters the object through contact. It is the most intimate form of manufacturing I have encountered in any industry.