Monochrome Watches
An online magazine dedicated to fine watches

A Closer Look At The Minase 7 Windows

Japan’s microbrand goes macro on case design and finishings.

| By Rebecca Doulton | 6 min read |
Minase 7 Windows

The Minase 7 Windows is not, as its name might suggest, a watchmaking ode to Microsoft’s operating system. It is a Japanese Minase watch with seven sapphire glass windows and a complex geometric case-in-case construction embellished with handmade finishings that could put many Swiss brands to shame. Let’s take a closer look at the new automatic Minase 7 Windows that reconciles a round peg (dial) in a rectangular case with distinctive Japanese verve.


If somebody brings up the subject of Japanese watchmaking, the conversation usually steers towards Seiko, Grand Seiko and maybe even Citizen. However, not many will mention Minase, a spinoff microbrand from Kyowa Co., a precision tool manufacturer since 1963. With its expertise in metalworking, Kyowa developed a precision step drill (useful for drilling crowns) and started manufacturing watch cases of ever-increasing complexity. One thing led to another, and Kyowa expanded its portfolio to include bracelet manufacturing and sophisticated polishing techniques. Finally, with all this experience under its belt, Kyowa decided it was ready to create its own watch brand, and in 2005, the watch brand Minase was born. Named after the workshop’s location in the Yuzawa mountains in the prefecture of Akita, Minase manufactures less than 500 watches per year and only recently started to expand at an international level.

The brand is very clear about one thing: Minase is all about bold Japanese design, spectacular metalwork and refined hand finishings, not movements. The mechanics are entrusted to Swiss ETA-based movements.  Habillage (external parts) is the keyword at Minase marked by a design philosophy, unlike anything we’ve seen from our usual suspects. Minase’s watches are characterised by steel architectural cases bristling with sharp angles, radical inclinations, jutting lugs, convex dials, and loads of personality.

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The Transformers of the watch world if you like, converted into beautifully crafted constructions that can vie with top dog GS. The 7 Windows is not a newcomer to Minase; it is an evolution of the 5 Windows that we covered in this Artistic Crafts version and the 15th-anniversary limited edition.

Time Capsules

Accustomed as we are to exploded views of movements, the exploded view of the 7 Windows case gives you an idea of the modular nature of Minase’s signature case-in-case construction. Starting in reverse order, the first step involves covering the movement inside a steel cover that acts as the dial plate. After this, Minase’s watchmakers mount an index ring on top of the dial plate, which is screwed into a matching casing ring on the reverse. The effect produced by this particular construction is that the round dial seems to be floating inside the rectangular case.

With its width of 38mm, length of 47mm and thickness of 13mm, the 7 Windows is a ‘borderline’ dressy watch, depending on how particular you are about case height. Admittedly, incorporating sapphire windows on the flanks of the case at noon and 6 o’clock diminishes the amount of metal and gives the watch an ethereal, lighter feel. With its raised polished claws clutching a black insert with the brand’s drill head logo, the crown is another example of the brand’s dexterity with steel.

Minase 7 Windows

The rectangular 316L stainless steel case features sweeping pagoda-like contours embracing the seven sapphire crystals windows. It might be a rectangular case, but the curvaceous profile and the suspended dial protected by a spherical sapphire crystal convey an almost liquid, organic feel. Oddly enough, for a watch with seven windows, you can only see the movement from the reverse side of the case.

Minase 7 Windows

According to Minase, artisans spend more than 20 hours on a single watch to produce the flawless mirror-polished and brushed surfaces. Like Grand Seiko, Minase also uses a polishing technique known as Sallaz polishing. Often referred to as black polishing, Sallaz (aka ‘Zaratsu’ polishing at GS) creates a mirror-like, distortion-free surface. Wearing gloves to protect their hands from cuts, Minase’s craftsmen polish the steel with a rotating tin plate coated with a fine layer of diamond dust.  Executed by only a handful of skilled artisans, Sallaz polishing requires great dexterity to calibrate the right amount of pressure and ensure that the corners don’t get rounded.  After each polishing, the metal is cleaned in a bath, and the process is repeated up to 45 times to achieve the spectacular mirror-like surfaces that embellish Minase’s cases.

Although it is available with a leather strap, the most interesting option is the model with an integrated steel bracelet. Inspired by traditional wooden Japanese puzzles, every part of the bracelet is an individual unit that can be disassembled and replaced. To ensure the right amount of play between the components, each segment of the bracelet is hand-cut and fastened from behind with screws. As you can appreciate in our photographs, there is plenty of breathing space between the links meaning the watch is ultra-flexible and extremely comfortable on the wrist. In addition, each link reveals a brushed surface with finely bevelled and polished edges.

Minase 7 Windows

Flooded with light from all angles, the convex blue sunray-brushed dial (also available with a grey or black dial) is chameleonic and, in certain light conditions, looks almost purple. A large rounded trapezoid on the dial, spanning from 3 to 6 o’clock, is set aside for the date function with seven numbers on view. The cut-out area for the date has a bevelled edge with the date disc on a lower lever for added depth. Almost like claws, the faceted and polished steel indices reach up to hug the curved contours of the dial. The index at 12 o’clock replicates Minase’s drill head logo. The steel hour and minute hands are polished and have a thin sliver of luminescent material and truncated tips. To follow the curvature of the dial, the minutes and seconds hands are slightly bent.

Minase 7 Windows

Customised Automatic movement

A few years ago, Minase introduced a 7 Windows model with a manual-winding movement and a power reserve indicator on the dial. The latest 7 Windows models are now equipped with automatic calibre KT7002 based on the Swiss ETA 2892/A2. Although it can only be seen from the sapphire crystal caseback, the movement is decorated by hand with perlage, diamond-polished bevels and a customised openworked rotor with apertures that resemble the brand’s drill head logo. Beating at 28,800vph/4Hz, the movement offers a power reserve of 50 hours.

Minase 7 Windows

Availability & price

The Minase 7 Windows is now available on the brand’s website, with delivery in mid-June 2021. Offered with a black, grey or blue dial, the models on a leather strap retail for CHF 4,300 and those on a steel bracelet for CHF 5,400. If you are in the market for one of these, do hurry because stocks are depleting fast.

For more information and to order a model, please visit

Sponsored Post: This article has been made in partnership with Minase. However, it reflects the writer’s opinion and has been written according to MONOCHROME’s editorial policy.

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