Minase Mastercraft J3 Brings the Japanese Watchmaker Back to 37mm

Minase has built its reputation on cases that feel closer to small architectural objects than conventional watch shells.

With the Mastercraft J3, the Akita watchmaker takes a quieter route, shrinking the format and sharpening the idea into a 37mm automatic that feels closer to the brand’s earliest instincts.

It’s also a notable shift under the dial, as Minase uses a Japanese movement for the first time in its history.

At a glance

• Minase introduces the Mastercraft J3, a compact 37mm automatic watch that revisits the spirit of its early M-series designs.
• The watch features Sallaz hand-finished case surfaces, sand-textured dials and a slim 9.9mm profile.
• Prices start at USD 2,050 on calfskin, with rubber and stainless steel bracelet options also offered.

A quieter chapter for an expressive case maker

Founded in 2005 as a spin-off from Kyowa, a specialist maker of watchmaking tools, Minase has become known for multi-faceted cases and unusually elaborate finishing.

Collections such as the Divido, Horizon and Windows helped define that identity, often using dramatic geometry, three-dimensional construction and generous sapphire elements.

The Mastercraft J3 moves in the opposite direction.

Its shape is more restrained, its diameter is smaller, and its emphasis is less on visual complexity than on proportion and surface treatment.

That makes it an interesting release for a brand whose appeal has often come from doing things the difficult way.

From the M1 to a more compact Mastercraft

The J3 is not simply a new small watch from Minase, but a return to a line of thinking that began with the M1 in 2005.

That early model was built around what Minase described as “ultimate simplicity”, using a 37mm integrated ultra-thin form to showcase the company’s case-making skill, although it used a quartz movement.

Later M2 and M3 models expanded the idea, with the M3 eventually reaching an international audience through collaborative editions known as “Very Peri”, “Nori” and “Shiro”.

The Mastercraft J3 takes inspiration from the tonneau-shaped M3 but tightens the formula, reducing the case from 38.8mm to 37mm and trimming thickness from 10.8mm to 9.9mm.

The result should appeal to collectors who like Minase’s finishing but found the brand’s larger or more sculptural pieces harder to wear day to day.

Sallaz finishing in a smaller frame

Minase describes the J3 case as cushion-shaped, though its silhouette has a helmet-like or bullhead-style quality with a hint of 1970s design.

The upper surfaces are brushed, while the bevels are finished with Sallaz mirror polishing, a technique Minase has made central to its identity.

On the J3, that finishing is used to create bright, distortion-free reflective planes and crisp edges across a much more compact case.

The round bezel is also mirror-polished, giving the pared-back shape a more assertive face without returning to the visual drama of the brand’s larger pieces.

Water resistance is rated to 50m, down from the 100m rating of the larger M3.

Sand-textured dials and a domestic movement

The J3 is offered with sand-textured dials in white, black or beige.

Each version uses stepped polished indices and matching hands with luminescent inserts that glow blue in the dark.

The raised peripheral precision track adds depth around the dial edge, with cutout sections shaped to accommodate the rectangular hour markers.

The movement choice is one of the more meaningful details in the J3.

Where the earlier Japan-only M3 used a Swiss Sellita SW200-1, the Mastercraft J3 adopts a Miyota 90S5 automatic calibre.

It runs at 28,800 vibrations per hour and offers a 42-hour power reserve, while its slim construction helps the watch maintain the 9.9mm case thickness.

A one-touch quick-change system adds practical range, allowing the watch to work with interchangeable calfskin, rubber and stainless steel bracelet options.

Details & Specifications

The Mastercraft J3 feels like a sensible expansion of Minase’s world rather than a retreat from it.

It keeps the hand-finished metalwork that defines the brand, but packages it in a more compact and accessible watch for collectors who want Japanese craft with less visual volume.