Citizen Eco-Drive 'Tsuki-Yomi' Radio-Controlled Moon Phase Blue 43mm Watch BY1010-57L

Introducing the Citizen 'Tsuki-yomi' Radio-Controlled Moon Phase - the world’s first light-powered radio-controlled moon phase movement. To celebrate the 30th anniversary of the first CITIZEN radio-controlled watch we are debuting the world’s first fully analogue moon phase function for light-powered watches. The Tsuki-yomi collection (directly translating to “reading the moon”) features a new radio-controlled Eco-Drive Cal. H874 movement that provides ±15 seconds accuracy per month, revolutionary proprietary Super Titanium™ material and artfully crafted moon pattern dials. Based on a unique mathematical formula developed by CITIZEN called “Luna Program”, the watch calculates the phase of the moon each day from signals received from multi-band radio transmitters. The phase of the moon at the six o’clock position is then automatically adjusted and displayed. With a striking blue pattern of the moon’s surface on the dial paired with a black outer ring, and date display at the 4 o’clock position. BY1010-57L