Details

Reference

No.5 Kai

Movement

Miyota 90S5 automatic

Case Material

stainless steel

Year

2026

Bracelet

black calfskin leather

Crystal

Sapphire crystal

Water Resistance

30 metres

About this watch

Jiro Katayama has long stood out in independent watchmaking for his non-conformist approach, creating watches with unusual display mechanisms and a distinctly industrial, Japanese aesthetic that deliberately avoids Swiss conventions. His Ōtsuka Lōtec brand first gained wider attention with the original No.5 in 2012, followed by refined versions of the No.7.5 and the No.6, which won a GPHG Challenge Prize. Over time the brand has evolved with production support from watchmaker Hajime Asaoka, another Japanese watchmaking legend. The No.5 Kai marks Katayama’s first entirely new design in many years and reuses the case architecture of his original 2012 No.5 while introducing a completely fresh satellite-hour system. Though it appears complex at first glance, reading the time is actually very simple - arguably easier than most regular watches (seriously). The hour on the right points to the minute on the arched disc. It also features a separate small rotating seconds disc positioned at the 6 o'clock position. The open-worked mechanism employs two custom Japanese ball bearings—one the world’s smallest steel bearing—to achieve smooth, instantaneous switching, all presented beneath a tal…