Grand Seiko unveils a second model in its Ultra Fine Accuracy (UFA) collection, the Evolution 9 Spring Drive UFA SLGB005. Featuring a violet-black dial inspired by Shinshu winter sunrises and powered by the latest generation spring drive technology, it represents everything Grand Seiko does best.

Limited to 1,300 pieces, the 37 mm SLGB005 is made from the brand’s proprietary Ever-Brilliant steel, an especially hard-wearing alloy that’s making its debut in the Evolution 9 Spring Drive line-up.

Initial thoughts

The Spring Drive UFA SLGB003 “Ice Forest” was arguably one of the most important releases of this year, finally delivering a long-awaited mid-sized Grand Seiko Spring Drive, complete with an adjustable clasp and tightened accuracy rating. The SLGB005 feels like a worthy counterpart in another metal, quantifiably excellent inside and out.

The SLGB005 retains the nearly perfect proportions of its titanium sibling at 37 mm in diameter and 11.4 mm thick, in a slightly heavier Ever-Brilliant steel case. Though Grand Seiko has used this material in the past, it’s the first time it’s been used for a Spring Drive watch in Evolution 9 guise, and also the first to be made at Shiojiri.

This is a new colour of an existing dial pattern. Grand Seiko’s dial work is always excellent, especially the hands and dial furniture, which are finished to unusually high standards.

The Spring Drive movement remains the same and excellent. While not mechanical, I’d argue that Spring Drive delivers everything many buyers of mechanical watches in this segment actually want: a smooth-gliding seconds hand, ‘set it and forget it’ accuracy, and some tangible degree of craftsmanship – all of which Spring Drive handily delivers.

As a consequence of being a limited edition, the watch is quite pricey at US$11,100. That’s slightly more than the otherwise identical titanium SLGB003, and also a tad more than a 36 mm Rolex Datejust in steel. I suspect we will see non-limited stainless steel cal. 9RB2 (or cal. 9RB1) powered models fairly soon, which helps stave off the “FOMO”.

Ever Brilliant

According to Grand Seiko, this deep red-violet gradient dial evokes a winter sunrise over the hoar-frosted forests of Mount Kirigamine, which looms over both Suwa and the nearby town of Shiojiri – from which all Spring Drive watches hail. After careful examination of Nagano nature photography, I’d say it is a reasonable likeness.

The texture is identical to the previous UFA models, SLGB001 in platinum and SLGB003 in titanium, which capture the same vista during the day.

Grand Seiko’s case finishing proficiency is as obvious in 37 mm as it is in 40 mm, and further emphasised by the Evolution 9 design language. The case is Ever-Brilliant steel, an unspecified alloy that surpasses even 904L stainless steel in corrosion resistance and is typically the domain of mechanical Grand Seikos – this is only the second Ever-Brilliant Spring Drive.

It also has superior polishability compared to titanium, which helps the SLGB005 shine, literally and otherwise. Like its titanium sibling, the watch is ready for anything with a screw-down crown and case back, and a 100 m water resistance rating.

The bracelet, also Ever-Brilliant steel to match the case, but does not include the brand’s new tool-free adjustment system, though the clasp does carry an 18k rose gold Grand Seiko medallion – a substitute for traditional gold case back medallions found on historical models with closed case backs.

High-tech and high-spec

Naturally, the SLGB005 is powered by the same cal. 9RB2 movement found in the SLGB003, which is rated to +/- 20 seconds per year. This distinguishes the movement from other Spring Drive calibres, earning it the UFA designation.

Like the cal. 9RA Spring Drive movements, the cal. 9RB2 uses both passive thermal insulation, with a vacuum-sealed quartz timing package, and active temperature compensation, which takes numerous temperature readings throughout the day and self-adjusts accordingly.

But unlike the cal. 9RA movements, Seiko officially specs the cal. 9RB2 to run within 20 seconds per year, hence the UFA distinction, which is an homage to the legendary VFA line.

Despite effectively being the smallest automatic Spring Drive yet made, the cal. 9RB2 is larger than most mainstream Swiss automatic calibres at 30 mm in diameter, easily filling the display case back.

In fact, it is the same diameter as the older cal. 9R65 inside the “Snowflake” and “Shunbun”, but can fit into smaller cases as the movement is inherently antimagnetic, while the cal. 9R65 requires extra space for a soft-iron ring around the movement.

When fully wound, the watch will run for almost exactly 72 hours, as tracked by an up/down indication on the case back with a fluted scale, which also adds visual interest to the single-plate calibre.

Key facts and price

Grand Seiko Evolution 9 Spring Drive UFA
Ref. SLGB005

Diameter: 37 mm
Height: 11.4 mm
Material: “Ever-Brilliant” Steel
Crystal: Sapphire
Water resistance: 100 m

Movement: 9RB2
Features: Hours, minutes, seconds, date, and power reserve on the movement side
Frequency: 32,768 Hz
Winding: Automatic
Power reserve: 72 hours

Strap: Steel bracelet with folding clasp and 18k rose gold medallion

Limited edition: Limited to 1,300 pieces
Availability: At Grand Seiko boutiques and retailers starting November 2025
Price: US$11,100

For more, visit Grand-seiko.com.