Citizen 'Tsuki-Yomi' Radio-Controlled Moon Phase 43mm Mens Watch

Ref. BY1010-57H

The grey dial carries a textured pattern of the moon's surface, framed by a black outer ring. The moon phase display sits at six o'clock, automatically adjusted each day using Citizen's Luna Program, which calculates lunar position from multi-band radio signals — making this the first light-powered watch to feature a fully analogue radio-controlled moon phase. A day sub-dial and date aperture at four o'clock complete the layout, with luminous hands and baton indices. The 43mm case and bracelet are both built from Super Titanium, keeping weight low on the wrist. A sapphire crystal sits above the dial, and the fold-over push-button clasp secures the bracelet. The solar Eco-Drive movement offers a six-month power reserve and covers 24 world time zones, with the perpetual calendar adjusting automatically for month lengths and leap years. Water resistance stands at 100 metres.

Reference

BY1010-57H

Brand

Citizen

Case size

43mm

Case material

Titanium

Dial

Grey

Crystal

Sapphire

Movement

Solar

Calibre

H874

Functions

Date, Moonphase

Water resistance

00m

Bracelet / strap

Stainless steel bracelet

Strap colour

Silver

Clasp

Folding clasp

Lume

Luminous

Retailer

Goldsmiths