To mark 145 years since Kintaro Hattori opened his Tokyo clock shop, Seiko has reissued the watch that started it all: the 1965 Prospex diver — Japan’s first purpose-built dive watch. The HBC005 is powered by the Calibre 6R55 with a 72-hour power reserve, features a super-hard coated stainless steel case, a silver-white aluminium rotating bezel with blue accents, and a bracelet with a diver-friendly clasp that adjusts in 2.5mm increments. It was our Watch of the Week for May 2026, and it earned that spot.
Why the HBC005 Is Special
The Seiko Prospex HBC005 is not just another anniversary watch. It is a faithful reissue of the watch that defined Japanese dive watch design — the 1965 Prospex, which was Japan’s first purpose-built dive watch.
The Calibre 6R55 inside is one of Seiko’s finest movements: 24 jewels, upgraded to a 72-hour power reserve in the HBC005. That means you can take it off on Friday evening and pick it up Monday morning and it will still be running. For a mechanical watch, that is exceptional.
The super-hard coating on the stainless steel case makes it significantly more scratch-resistant than standard stainless steel. The silver-white aluminium bezel insert with blue accents is a nod to the original 1965 design, and the bracelet’s 2.5mm micro-adjustment clasp is a practical detail that most watch brands charge $1,000+ to include.
The 145th Anniversary Context
Seiko was founded in 1881 when Kintaro Hattori opened a clock shop in Tokyo’s Ginza district. In 145 years, the company has grown from a small clock retailer to one of the world’s most respected watchmakers — responsible for innovations including the world’s first quartz watch (1969), the world’s first GPS solar watch (2012), and the Spring Drive movement.
The HBC005 is one of a small number of limited-edition pieces released to mark the 145th anniversary. It is not a concept watch or a museum piece — it is a fully functional, daily-wearable dive watch that happens to carry the heritage of 145 years of Japanese watchmaking.
Who Should Buy the HBC005?
The HBC005 is the right watch for:
– **Seiko collectors** who want a piece with genuine historical significance
– **Diver watch enthusiasts** who want a Japan-made automatic diver with a 72-hour power reserve
– **Investors** who recognise that limited-edition Seiko anniversary pieces tend to appreciate in value
– **Watch enthusiasts** who want a watch that can be worn every day but will also be a conversation piece
At $595, it is not a budget watch — but for a Japan-made, limited-edition Seiko Prospex with a 72-hour power reserve, it represents genuine value.
The Seiko Prospex HBC005 was our Watch of the Week for May 2026. It is the rarest thing in watchmaking: a limited-edition anniversary piece that is also genuinely wearable every day. At $595 for a Japan-made, limited-edition Seiko Prospex with a 72-hour power reserve, this is the kind of watch that will be worth more in five years than it is today.
[Check availability on Amazon →](https://www.amazon.com/dp/B0CXMHK1J4?tag=ijgprojects-20)
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