The Seiko Prospex HBB001K1 is the "Samurai" in Seiko's second wave of 145th Anniversary commemorative limited editions — the more compact, more accessible, and more angular of the two 145th Anniversary Prospex divers, alongside the HBC005 1965 Heritage. Limited to 9,999 pieces worldwide, the HBB001K1 pairs the updated Samurai case platform introduced in 2024 with the "Seiko Blue" accent treatment that defines the entire 145th Anniversary series: a blue aluminium unidirectional rotating bezel, a blue seconds hand, and a silver-white dial that creates the clean, cool, distinctly modern presentation that has made the Seiko Blue series the standout aesthetic of the anniversary range.

The "Samurai" nickname — given by Seiko collectors for the angular, blade-like case surfaces that define the case shape's visual character — belongs to a platform that received a meaningful update in 2024: the case diameter came down to a more wearable 41.7mm, the thickness is 12.3mm slim, and the lug-to-lug at 49.5mm wears more comfortably than earlier Samurai generations. The chamfered centre links on the solid stainless steel bracelet reflect the same angular design language as the case, creating a unified aesthetic that runs from dial to clasp. Powered by the 4R35 automatic calibre with hand-winding and stop seconds, it delivers dependable everyday performance at Diver's 200M water resistance with Lumibrite on the hands, indexes, and bezel for complete low-light legibility.