For the first time, a radio-controlled calibre is enhanced with a moon-phase display. State-of-the-art technology and materials borrowed from the aerospace industry thus coexist with the most poetic of complications. In Citizen Tsuki-Yomi's 43 mm diameter case and bracelet are made of Super Titanium with Duratect MRK treatment, which makes the metal surface more resistant to scratches and shocks than the 40%. This is a Citizen-patented alloy that is light, resistant and hypoallergenic and for whose aerospace applications the Tokyo-based company has entered into a partnership with a number of Japanese companies.
The dial, available in blue, green, grey or burgundy, is decorated with a reproduction of the visible face of the moon. At 6 o'clock is the moon phase indicator, at 9 o'clock is the circular day/night indicator, and at 4 o'clock the date display. The multifunction counter at 12 o'clock can indicate the day of the week, the power reserve and the earth's hemisphere you are in (the only data to be set manually).
The movement is the calibre H874, which combines the Eco-Drive solar-powered system with radio-controlled technology and, above all, a moon-phase complication. The radio-controlled technology allows the watch to receive the time indicated by the five existing atomic clocks (located in Germany, China, the United States and two in Japan) every 24 hours, usually at night. In this way, the time and date are always correct and the phases of the moon, stored up to 2100, are adjusted in real time.
The margin of error basically does not exist, as it has been estimated at one second per 100,000 years. Citizen's engineers, however, realised that the hands can still be in the wrong position in relation to the received data due to physiological play between the gears, small shocks or magnetism. To remedy this, they developed an additional technology (also patented and christened 'Perfex') that automatically monitors and corrects such errors with the necessary micro-adjustments.
This also applied to the moon phase display opens up a new chapter. Until now, the manual adjustment of this complication on analogue watches was itself a 'complication'. In order to set the moon symbol to the exact position, it was necessary to be equipped with a calendar, glasses (often) and a great deal of patience (always), with the result that, within a few weeks, the display would no longer be correct and would turn into a purely aesthetic ornament. With the Citizen Tsuki-Yomi, there is no laziness or presbyopia to worry about, and the fact of always knowing the exact position of the Moon without any intervention is an undeniable added value.
Price698 euro.
