Citizen has launched a new Eco-Drive One measuring just 3.88mm thick, squeezing its light-powered technology into a case slimmer than many everyday yoga mats.
The new AR5065-54W pairs those ultra-thin proportions with a 38mm black stainless steel case, forest-green dial and matching bracelet. At less than four millimetres from front to back, it is remarkably slim without looking like an engineering experiment.

Getting the case that thin starts with Citizen’s Calibre 8826 Eco-Drive movement, which measures only 1mm thick. It converts natural or artificial light into energy, removing the need for regular battery changes, and can run for around a year once fully charged.
Citizen keeps the rest of the watch fairly restrained to suit those proportions. Forest green covers the dial, with pink-gold-coloured details adding some warmth against the black case and bracelet. Anti-reflective sapphire crystal protects the front, while the integrated stainless steel bracelet closes with a push-button folding clasp.

Its slim profile has not stopped Citizen from adding a few useful everyday features either. Water resistance is rated to 5 bar, or 50 metres, and the complete watch weighs 96g. Mechanically, things stay simple with just hour and minute hands.
The Eco-Drive One line has been around since 2016, built around the idea of making light-powered watches as thin as possible. This latest version gives that formula a slightly sportier look through its angular case and integrated bracelet.

It is also a limited release, though Citizen’s regional websites currently disagree on exactly how limited. The Japanese site lists 180 pieces worldwide, while the US page says 250.
Pricing sits at $3,395 in the US. That is a lot for a two-hand quartz watch, but packing a 1mm light-powered movement into a 3.88mm case gives this Citizen a fairly unusual reason for costing so much.