No. 6

The No. 6 is the watch that carried independent Japanese watchmaker Jiro Katayama's name beyond his home market. Like every Ōtsuka Lōtec, it is produced in tiny numbers — fewer than 200 watches leave Katayama's workshop each year, sold domestically by lottery — yet it became the unlikely object of international attention, distilling the brand's steampunk aesthetic and inventive mechanics into its most celebrated form.

With its eight-screw bezel, straight-brushed steel case, and instrument-like dial layout, the No. 6 is evocative of vintage industrial meters, particularly analog pressure gauges. The retrograde hour and minute indicators are powered by a modified Miyota 9015 Caliber, fitted with a proprietary module developed in-house. Exposed hardware and minimalistic text elements enhance the mechanical, function-first character of the piece.

The model was nominated for — and ultimately won — the 2024 GPHG “Challenge” Prize, marking a significant milestone for Katayama and drawing global attention to the quietly revered Japanese atelier.