Black Persimmon Five watch ku5k-170

It is said that only one tree out of a thousand develops these markings. Even when found, the usable material is very limited due to small log size, cracking, warping, and the irregular nature of the grain, making careful selection and matching essential.

Unlike typical fine woods that show beauty through growth rings alone, Kurogaki features distinctive figured grain layered over the annual rings. The material used here displays clear striped figuring, with additional burl-like patterns appearing simultaneously—an exceptionally rare combination even among Kurogaki.

This is a material seldom encountered, offering a truly one-of-a-kind expression.

The many treasures housed in the Shōsōin Repository, crafted from Kurogaki, prove that Kurogaki woodcraft already existed some 1,300 years ago. While the culture of Kurogaki is believed to have been passed down through generations of makers, it was further revitalized through the tea ceremony. Over time, it came to be cherished by daimyō, high-ranking samurai, and wealthy merchants as a prized timber for their residences and as a material for tea utensils.

SIZE W355 D124 H110

MATERIAL Black Persimmon  / Ultra suede lining

Designed by Toshihiro Kamei

Cushions are available in three sizes: S / M / L.
Please choose the size that best fits your wrist. We Will contact you for the cushion size after you have completed the purchase.

 S:14~16cm  M:17~19cm  L:20~22cm

【Characteristics of KOMA watch case】

Grain Matching

By carefully arranging and cutting each component in sequence, the wood grain flows seamlessly from one piece to the next. With meticulous attention to detail, our skilled craftsmen match the grain one by one—honoring the natural beauty of the wood and bringing out its finest expression through both refined aesthetics and expert technique.

Mitered Joinery 

By joining the top, side, and front panel with precise 45° miters, the grain continues uninterrupted, creating a beautifully seamless finish. This technique also provides excellent structural strength and helps prevent misalignment at the joints over time.
It is a highly advanced method that requires exceptional skill and a great deal of time and effort.

Assembling

Assembling mitered joints is an intricate process that can only be achieved through skilled handwork.

For both the upper and lower sections, dozens of specialized clamping tools—such as shakoman and hatagane—are used to secure the wood in place. It is an extremely delicate step, where even the slightest difference in pressure on each clamp can affect the final alignment.

Spline Reinforcement

To reinforce the corners formed with mitered joinery, a 0.5 mm wooden spline is carefully inserted into the joint.
This not only increases overall strength, but also creates a distinctive and beautiful detail—an expression unique to fine craftsmanship.

Finishing / Oil Treatment

Each piece is carefully refined with hand planes and sandpaper to enhance the grain and bring out the full natural beauty of the wood.
Before applying the oil finish, we seal the surface pores as a base preparation. This helps prevent water rings and staining, while achieving an exceptionally smooth, silky feel to the touch.

Please note: To preserve the wood’s natural beauty and texture, we do not use polyurethane coatings or colored stains.

Concealed Hinges

When the box is closed, the hinges are completely hidden from view at the back.

As the interior is fully finished, no hardware is visible from any angle—preserving the box’s clean, seamless design and the beauty of the wood grain.