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Citizen Tsuyosa Automatic Small Seconds 40mm Unisex Watch
Ref. NK5010-51L
Sits in Citizen’s upper tier here — more premium than three quarters of the Citizen watches we list, which start at £139.
Price range £139 to £1,145 across 79 Citizen watches in stock.The blue dial carries a stamped guilloché-like texture that gives it depth without relying on colour alone. A small seconds sub-dial sits at six o'clock, and a power reserve indicator rounds out the layout. Hands and baton indices carry luminous material, and the crystal is sapphire with an anti-reflective coating. The crown is recessed at four o'clock. At 40mm across and 11.7mm thick, the stainless steel case wears on an integrated three-row bracelet with a double push-button butterfly clasp and quick-release spring bars. The screw-in case back is exhibition. Inside, Citizen's Calibre 8322 runs at 21,600vph with a 60-hour power reserve and hacking seconds.
- Reference
- NK5010-51L
- Brand
- Citizen
- Collection
- Tsuyosa
- Case size
- 40mm
- Case thickness
- 11.7mm
- Case material
- Stainless steel
- Case shape
- Round
- Dial
- Blue
- Crystal
- Sapphire
- Movement
- Automatic
- Calibre
- 8322
- Functions
- Small seconds
- Water resistance
- 50m
- Bracelet / strap
- Stainless steel bracelet
- Strap colour
- Silver
- Clasp
- Butterfly clasp
- Lume
- Luminous
- Retailer
- Goldsmiths
Additional specifications
- Lug-to-lug
- 45.7mm
- Power reserve
- 60 hours
- Weight
- 147g
- Strap
- Interchangeable
Learn more about Citizen
The Shokosha Watch Research Institute began in Tokyo in 1918, and the Citizen name was given to its first pocket watch in 1924 by the then mayor of Tokyo, Shinpei Goto, who wanted a watch that would be available to ordinary citizens rather than only the wealthy. The company formally took the name in 1930.
That founding intention has held. Citizen is the largest watch manufacturer in the world by volume and is fully vertically integrated, making its own movements, cases, and electronic components.
Its most significant technology is Eco-Drive, introduced in 1976 and refined over decades. A photovoltaic cell beneath the dial converts any light — including indoor light — into stored energy, so the watch never needs a battery change. Citizen has sold well over a hundred million Eco-Drive watches, and the environmental argument is substantial: hundreds of millions of cells not discarded.
The company also produced the first analogue quartz watch with a titanium case in 1970, the first professional dive watch with an electronic depth sensor, and the Caliber 0100, an Eco-Drive movement accurate to within one second a year — the most accurate independent watch movement ever put into production.
Citizen owns Bulova, Frederique Constant, Alpina, and the movement manufacturer Miyota, whose calibres power a large share of the affordable mechanical watch market worldwide.
- 1918
- The Shokosha Watch Research Institute is founded.
- 1924
- The Citizen name is given to its first pocket watch.
- 1976
- Eco-Drive light-powered technology is introduced.
- 2018
- The Caliber 0100 achieves accuracy of one second a year.
Also in 6 collections
This watch appears in the Citizen Tsuyosa range (19), Back in Stock (3,236), Stainless Steel Watches (2,946), Automatic Watches (1,744), Blue Dial Watches (813) and Automatic Watches Under £500 (301).
Manufacturer’s guarantee
What the specifications mean
A mechanical watch for everyday wear.
Strengths
- 40mm suits most wrists
- 45.7mm lug-to-lug keeps the 40mm case wearable
- Sapphire crystal, which resists scratching
- Luminous hands and markers for low light
- One of Citizen's more premium watches
Worth knowing
- 50m suits rain and handwashing, not swimming
Citizen Tsuyosa alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | NK5010-51L | T1584071604100 | SRPL73J1 |
|---|---|---|---|
| Price | £399 | £408 | £399 |
| Case size | 40mm | 40mm | 39.5mm |
| Water resistance | 50m | 50m | 50m |
| Movement | Automatic | Automatic | Automatic |
| Strap | Stainless steel bracelet | Leather strap | Stainless steel bracelet |
| Power reserve | 60 hours | 80 hours | — |
| This watch | Closely matched | Closely matched |
Your new watch
Frequently asked questions, and things you should know about this watch
Can I swim with it?
Showering yes, swimming no. 50m covers splashes and brief immersion, but a swimming stroke generates well above the pressure that figure describes.
Water resistance explainedWill the glass scratch?
Unlikely. Sapphire is second only to diamond in hardness and shrugs off everyday marking.
Sapphire, mineral and acrylic comparedDoes it need a battery?
No. It is automatic — the motion of your wrist winds it, and there is no cell to replace.
Quartz, automatic and solar comparedHow long does it run for when it's not worn?
About 60 hours fully wound — enough to survive a night off the wrist, but not a full weekend.
Will it fit my wrist?
Lug-to-lug is 45.7mm, which suits wrists from roughly 16cm (6¼ inches) upward.
Lug-to-lug decides fit more than case diameter does.
How to size a watch to your wristIs it a men's or women's watch?
Listed as unisex, and at this size it suits any wrist that takes the dimensions.
Cheapest place to buy
Goldsmiths is the only UK retailer we track stocking this reference, so there is nothing to compare it against today.
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