Like most world records, “the world’s most accurate watch” is a moving target and almost always requires some qualification. The technology was announced in 2018, but the wristwatch to contain the super-accurate Citizen Caliber 0100 quartz movement debuted at Baselworld 2019. It’s accurate to within one second per year and prices start at over $7,000.
To put this in perspective, most quartz watches measure their accuracy per month, and even the most accurate traditional mechanical watches measure per day. Citizen beats high-end quartz watches like those from Grand Seiko with estimates of +/- five seconds per year. The difference between five seconds and one second per year might sound insignificant, but consider it five times more precise, and refinements at this level get exponentially more complicated. While some watches use various external sources via the likes of radio signals or internet to regularly synchronize with atomic clocks, Citizen can claim to have the most accurate autonomous movement.
The brand explains that one thing they did differently for the Caliber 0100 was to replace the quartz crystal’s typical tuning-fork shape with something called an “AT cut” (previously used in watches only very rarely). This has a number of benefits for stability and resistance to temperature and position changes, but it also oscillates at 8 megahertz rather than the 32 kilohertz of the traditional shape (256 times faster). Citizen goes into the technical details of how it all works in this video, and there’s a lot more cool stuff going on with this watch if you care to put on your nerd glasses.
Citizen combined other technologies such as an integrated circuit designed to correct minor temperature-caused deviations, as well as the brand’s well-known Eco Drive, so the battery is powered by light. One cool feature of the new watches is that the brand displays the movement through a case back window, which is very uncommon for quartz watches. The wristwatches containing this remarkable movement measure 37.5mm wide and a thin 9.1mm with 50m of water-resistance. Versions in hardened titanium cases will be priced $7,400 and limited to 200 pieces for a mother of pearl dial and 500 pieces for the black dial model. A white gold case version will cost $16,800, and all will be available in Fall 2019.