Grand Seiko’s Latest is the Thinnest Automatic Spring Drive Yet

If you engage with Grand Seiko collectors in a meaningful way on the internet and social media, you’ve almost certainly been part of a conversation that relates to watch thickness. Grand Seiko watches, as beautiful as they are, and as much as many of us love them, have always had some heft to them. At least, they measure that way. A large part of the discourse on forums and such is “But they wear thinner!” And they do, thanks in large part to the unique geometry of many Grand Seiko cases. The thickness on these watches is often disguised behind generous Zaratsu polish, and even transformed into an attribute if you’re into admiring expansive and expertly finished bevels. Still, there’s no doubt that the trend in the watch industry, particularly among vertically integrated brands that have know-how, is to make watches thinner, and more wearable, with the help of new movements that allow for more svelte dimensions. Grand Seiko has been moving in this very direction with an assist from the 9SA5 movement, a high frequency caliber found in the White Birch that Zach W. reviewed just last week. But what if Spring Drive is more your thing? Grand Seiko’s next generation 9RA5 Spring Drive caliber was introduced last year in a limited edition dive watch that was anything but thin, which has led enthusiasts to wonder when an automatic, Spring Drive equipped watch would take center stage. Well, with the new SLGA007 that Grand Seiko has just unveiled, that time has (almost) come. 


The new watch is part of Grand Seiko’s Heritage Collection, and features a textured blue dial that Grand Seiko explains is inspired by the water of Lake Suwa, located near the brand’s Shinshu Watch Studio. This, of course, is a familiar formula at this point. Grand Seiko has been crafting dials inspired by the natural world for years, and the textured pattern here is not too far removed from the aforementioned White Birch or the recent batch of new Grand Seiko “Seasons” watches. The blue is given gold accents by way of the Grand Seiko wordmark at 12:00 the smooth gliding seconds hand. Hour markers  and hands appear to be in the same style as the White Birch, which means everything is thick, diamond cut, and highly polished. The handset in particular feels like an evolution for the brand, and as Zach points out in his review of the White Birch, this newer hour hand design feels sportier thanks to hand’s thickness and the ridge running down the middle, which feels like an invite to make these new watches everyday wearers. A full 100 meters of water resistance, screw down crown, and stainless steel bracelet also help to strengthen the case for the SLGA007 as an everyday timepiece. 

And given the watch’s proportions, this could easily be worn day in and day out. The 40mm case is only 11.8mm thick, making it the thinnest automatic Spring Drive movement in Grand Seiko’s catalog. The Snowflake, reference SBGA211, often thought of as the Spring Drive standard bearer, measures 12.5mm thick, by way of comparison. The hand wound SBGY007 is just over 10mm thick, but that’s a pure dress watch, and would seem to be a very different thing than the SLGA007. While 11.8mm certainly isn’t breaking any thinness records, it’s a meaningful improvement for an self-powered Spring Drive watch, and seems like the kind of watch a lot of Grand Seiko collectors have been waiting for for a very long time. 

To that end, the real star of the show here is the new movement that Grand Seiko is introducing in the SLGA007, the Caliber 9RA2, with 120 hours of power reserve. This movement has specs that match last year’s 9RA5, but with the power reserve indicator moved to the backside of the movement, which makes for a cleaner dial and scratches an itch that many would-be Spring Drive consumers have been reaching for from the beginning. According to Grand Seiko, the movement’s height of just 5mm is achieved through a repositioning of the “Magic Lever” (used in Seiko watches since the 60s to increase winding efficiency) to a space outside of the watch’s center. Like the 9SA5, the 9RA2 is finished more extravagantly than previous Grand Seiko calibers. The new Spring Drive caliber has been given a textured finish that Grand Seiko hopes will invoke a winter’s frost, and bevels have been diamond cut. In terms of timekeeping performance, the new caliber is rated to the same +/- 10 seconds per month as the 9RA5, which would be a mind boggling accomplishment if we weren’t somewhat used to it from Grand Seiko. 

Unfortunately, the new SLGA007 won’t hit stores until December. Even more unfortunate, it’s a limited edition of 2.021 pieces. And the price point, depending on your budget, might be even more bad news, as this watch is set to sell for $8,700. That’s not inexpensive, but given the clear improvements that have been made to the movement, and what we expect to be the same exceptional Grand Seiko finishing we’ve seen in their recent work (we’ll be sure to let you know once we get hands-on with one), the price does not seem unfair. More information can be found at Grand Seiko’s website, right here

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Zach is a native of New Hampshire, and he has been interested in watches since the age of 13, when he walked into Macy’s and bought a gaudy, quartz, two-tone Citizen chronograph with his hard earned Bar Mitzvah money. It was lost in a move years ago, but he continues to hunt for a similar piece on eBay. Zach loves a wide variety of watches, but leans toward classic designs and proportions that have stood the test of time. He is currently obsessed with Grand Seiko.