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Atomic Timekeeping / Super Titanium
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When breakthrough technology and spectacular design meet, the Tsuki-yomi A-T is reading the moon. It’s the world’s first moonphase watch combined with atomic timekeeping innovation from Citizen, and this 30th Anniversary model is nothing short of impressive. The styling embodies the moon’s surface and a window at 6 o’clock displays the current moon phase. The timepiece measures 43mm in a silver-tone Super Titanium™ case, where sharp faceted edges pair with an elevated design throughout for an eye-catching aesthetic on the wrist. The grey dial works in tandem with black accents and silver-tone touches for a display that’s as handsome as it is legible. In addition to its running time, the watch features a moon phase display, world time in 24 time zones, a perpetual calendar, and day-date functionality. Powered by Citizen’s proprietary Eco-Drive technology to provide light-powered vitality without ever needing a battery. Water resistant up to 100 metres. Calibre H874.

Tsuki-yomi A-T
5 Year limited warranty
Free Shipping on all orders


Product Details
Model
- BY1010-57H
Movement Technology
- H874
- Eco-Drive
- Powered by any light source, continuously and sustainably, eliminating the need to replace watch batteries.
Case Size (mm)
- 43
Lug Width (mm)
- 22
Band Type
- Bracelet
- Super Titanium
Case Material
- Silver-Tone
- Super Titanium
Crystal
- Sapphire Crystal
- Superior scratch resistance and hardness
Clasp
- Fold Over Clasp with Push Button
Dial
- Grey
Water-Resistance
- WR100/10Bar/333ft (Swimming, Marine Sports)
Additional Functions
- Moonphase Indicator
- World Time in 24 Time Zones
- Day/Date
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Reviews

The watch is very light and easy to use. It has great features and value for the price. The satellite feature is very responsive and adjusts time with high precision.

Just purchased the Tsuki-Yomi A/T and I'm very pleased. The watch is very well made and the super titanium construction makes it very light and comfortable to wear. I never have to worry about setting it because every night without fail it recieves the signal from Fort Collins and updates the time. I now use this watch to set all my automatics in my collection. Alot of watch for the money!

I love my watch. It is well crafted, light weight, and my new everyday watch. ☆☆☆☆☆

The eco watches are the best. Solar never wind. People always say I love your watch.

Until I got this watch, I have always looked down on non-automatic watches especially those outside the Rolex/Tudor, Omega/Blancpain/Longines, Cartier/JLC/Piaget universe. Not anymore. The accuracy of this watch matches my watch’s; I’m gobsmacked. And it certainly doesn’t hurt that this watch is pretty posh-looking and light, too.

It took me a while to find a replacement for my old watch, which I lost because of a weak spot. That is the pin, which holds the bracelet. It had a sintered metal case and saphire crystal, almost 40 years old and looked like new. I am anticipating the same from this exquisite timepiece. I had zeroed in on the Sport Luxury AT8267-51X, looks really sharp, but titanium beats stainless steel. The instructions on the video are very easy to follow on www .citizenwatch.com/us/en/product/BY1010-57H.html?cgid=mens-super-titanium

This watch is really cool, I love the moon dial its not really gray in my opinion but bluish purple, more organic than gray. Just like the moon, it picks up the RC signal with no issues and the date window is really easy to read. The loom is impressive and lasts a long time, overall very happy with this watch. World time is easy to change and you have a diagram on the back of the watch to know how to set your time zone.

I’m very satisfied! This watch was difficult to obtain… yet.. you put me in waiting list.. finally got it!!
Great watch! But only as long as Citizen sends it charged and synced to the corrected time and date. I sent back an earlier watch that was delivered dead, and, once charged, I could not get the time, date, and year all set. All I had to do with this second watch was set the time zone. Gorgeous watch! Great features!
I just bought this a few weeks back, I love it. I enjoy that it won’t need a battery, and that it syncs up to the correct time every day. It is super light compared to my stainless steel watches. All I will say is when you go to resize it, it has collars for the pins, don’t lose them like I did.
As my third Citizen Eco-Drive watch over the last 23 years, I’m absolutely delighted with this watch, the craftsmanship, and features.
As my third Citizen Eco-Drive watch over the last 23 years, I’m absolutely delighted with this watch, the craftsmanship, and features.
As my third Citizen Eco-Drive watch over the last 23 years, I’m absolutely delighted with this watch, the craftsmanship, and features.
This watch is an absolute showstopper. Looks great, and the radio update was easy and accurate. Follow the instructions for some initial setting and you’re all set. A lot of compliments on my new addition.
Very good watch. I love it . The moon phase is amazing . Light weight. It’s just the best watch I ever had. And I prefer quartz watches more then automatic ones .
Very good watch. I love it . The moon phase is amazing . Light weight. It’s just the best watch I ever had. And I prefer quartz watches more then automatic ones .
This is a beautiful watch. Very light titanium bracelet and case and the dial is amazing! A-T makes it sweeter!
Exceptional everyday watch!
This is a very well built watch. Surprisingly, light weight titanium dial and bracelet. It fits very well on my 7 inch wrist. I had it customized to remove some brackets at the Citizen store when I bought this. Unfortunately, I wasn't able to get the radio signal atleadt here in CT and NYC. But I guess it depends on the location.
Great Space Themed Titanium Watch
Lightweight, tough and classy. Has all the essential functionality of a true, "set and forget" watch with an eye catching moonscape watch face. As an Astronautical Engineer myself, it was a must have!
Best Moonphase watch.
Well, I thought about this watch for some time before buying. It is a master piece of watch technology, and it was well designed.
Citizen Response Thank you for your review! We’re happy to hear you made the perfect choice with your new Tsuki-yomi A-T watch. We appreciate your feedback on the technology and design as it’s the world’s first moon phase watch combined with atomic timekeeping and Eco-Drive technology. We hope you enjoy your new watch for many years to come!
Isao
excellent.