Chronograph week continues with another 8100A single register model – with no model number, this is identified by its case number – 4-900014. After a recent discussion with a fellow collector, we reckon that the model numbers used on many watches, for example yesterday’s 67-9577, were for international markets, whilst Japanese Domestic Market (JDM) models use only the case number. This is supported by the catalogues I’ve seen – Japanese language ones use a different reference number system alongside the case number, but German and Australian catalogues have the 67-9577 type model numbers. So I also reckon that today’s watch was sold only on the JDM initially – and this one was made in May 1972, which was the month when the 8100 models were first launched.

Today’s piece has a polished stainless steel case with black bezel (case material code SSB), with a black dial and sub-register with colour highlight. Along with black day and date rings, white baton hour markers and white hands, this is a smart design that has stood the test of time very well in my opnion. As with all the 8100 and 8110 chronographs it can be hand wound and has ‘fly-back’ capability, i.e. instant zero’ing and restart: