Otsuka LotecJumping Hour Steel Watch No. 7.5

Description

The Otsuka Lotec No. 7.5 replaces the conventional dial entirely with a small window-and-disc mechanism, the signature approach of its Tokyo workshop. The hour numeral changes instantly at the top of every hour in the jumping-hour window, while the minutes track along a rotating disc beneath a fixed scale, producing the brand’s characteristic mechanical snap at each hour change, alongside a small seconds indicator. Otsuka Lotec was founded by Jiro Katayama, an industrial designer by training rather than a traditional watchmaker, and that background shows immediately in the No. 7.5’s construction: the layered, bead-blasted steel plates that make up the display were inspired by vintage camera lenses and laboratory instruments, giving the watch the presence of a precision instrument rather than a conventional dress or sport piece. The self-winding movement is built on a Miyota 82S5 base, onto which Katayama adds his own jumping-hour module, a deliberate choice that lets him focus his limited workshop time on the display mechanism rather than developing a movement from scratch. The 40mm stainless steel case is fitted to a black leather strap. Production is extremely limited, assembled by a small workshop that for years sold almost exclusively to Japanese residents through an internal lottery system, which has made international examples like this one genuinely difficult to find outside the secondary market.

This is an unworn Otsuka Lotec No. 7.5 Jumping Hour Steel Watch No. 7.5. It comes with the manufacturer’s box and papers.

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