Orient Star M45 F8 Mechanical Moon Phase Hand-Winding Review

Marking its 75th anniversary in 2026, Japanese watchmaker Orient Star has launched the M45 F8 Mechanical Moon Phase Hand-Winding, featuring a dial created using patented metal nanoparticle lamination technology. Priced at 462,000 yen, the limited 100-piece mechanical timepiece showcases an abstract depiction of “the moon among clouds.”

Engineering the 75th Anniversary Milestone

Founded in 1950 as Tama Keiki before introducing its signature star-branded timepieces a year later, Orient Star entered its milestone 75th anniversary year in 2026. Among the commemorative releases sits a technical piece that quietly pushes the brand’s manufacturing capabilities forward: the M45 F8 Mechanical Moon Phase Hand-Winding (Cal.F8A62), scheduled for release on October 29, 2026, according to Chronos-Japan reporting by Chieko Tsuruoka.

The watch takes its designation from the M45 class—better known as the Pleiades star cluster, or “Subaru” in Japanese. True to this celestial theme, the dial pairs a power reserve indicator with a sophisticated moon phase complication. But the true engineering narrative lies within the dial itself, manufactured at the Shinshu Watch Studio.

Metal Nanoparticle Lamination and the “Cloud-Filtered Moon” Effect

At first glance, the watch presents a restrained aesthetic. Look closer at the dark background, however, and you notice a randomized shimmering pattern. According to Chronos-Japan, this optical effect is achieved through a patented metal nanoparticle lamination technology.

The process deploys 30nm metal nanoparticles, printed onto the dial across multiple layers. This precise vertical stacking controls color intensity and gradation. As the viewing angle shifts, the reflected light refracts differently across the micro-layers, creating a shimmering optical illusion where the moon appears to drift behind drifting clouds. A clear topcoat (wrapping process) seals the structure, enhancing the depth of the dark dial while preventing ink degradation over time.

This technical execution builds directly on Orient Star’s recent material experiments. Last year, the brand introduced the Contemporary Collection M34 F8 Date (Ref. RK-BX0007B), which utilized the same nanoparticle architecture to render the Perseus meteor shower. While utilizing the identical core printing technology, the new M45 iteration shifts from dynamic shooting stars to a softer, diffused lunar glow.

Inside the Caliber F8A62 Hand-Winding Movement

Turning the watch over reveals the hand-wound Caliber F8A62 through a display caseback. Because it lacks an oscillating rotor, the architecture exposes the bridges designed to frame a blue silicon escape wheel alongside a wave pattern inspired by stellar tracks and a crescent-shaped cutout.

Originally introduced alongside the Ref. RK-BW0001S model, the Caliber F8A62 separates the moon phase mechanism into a distinct three-tier construction consisting of a disk, a mother-of-pearl moon, and a gear train. This layout allows for tighter tolerances between the dial surface and hands, reducing the height of the dial flange and letting the moon phase graphic blend naturally into the nocturnal backdrop.

Despite its classic presentation, the internal specifications are thoroughly modern. The movement integrates a proprietary silicon escape wheel, delivering Class 1 anti-magnetic resistance (4800 A/m or higher) and an approximate 70-hour power reserve.

Specifications and Availability

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• Model: Orient Star M45 F8 Mechanical Moon Phase Hand-Winding
• Movement: Hand-wound Cal.F8A62 (20 jewels, 2万1600振動／時)
• Power Reserve: Approximately 70 hours
• Case Material: Stainless steel (39.5mm diameter, 11.9mm thickness)
• Water Resistance: 3 bar
• Production: Limited to 100 pieces (20 via the official online store; 80 bundled with an extra strap via the official online store and prestige shops)
• Pricing: 462,000 yen standard; 484,000 yen with extra strap (tax included)
• Release Date: October 29, 2026