If the Seiko Turtle appeals but its dimensions put you off, the Citizen NY0040 deserves a place on the same shortlist. The current European NY0040-09EC is a straightforward automatic diver with a black dial, black urethane strap and a case that asks less of your wrist. The decision is mainly about fit, controls and whether you enjoy owning a mechanical watch.
This guide covers the exact NY0040-09EC listed by Citizen Europe. Older NY0040 references and examples with different movements also exist. The final letters and the calibre matter when comparing offers.
Based on Citizen’s published information. Specifications checked on 8 September 2026.
A design built around rounded surfaces
Citizen’s design archive records the NY0040-09W, a related family member, as a 1997 watch designed by Akihiko Kuroda. Its account concentrates on the relationship between a diver and the person wearing it. The rounded back was intended to reduce the sense of a hard object pressing against the wrist, while the recessed bezel contours provided purchase for gloved fingers. Six rounded projections interrupted the bezel’s outline. This is useful history because it explains the NY0040’s distinctive shape without relying on military stories. The archived watch used calibre 8203; the current European reference here lists 8204. The original design account describes the family’s intentions, rather than proving how any individual current example will feel on your wrist.
Specifications for the NY0040-09EC
| Detail | Published specification |
|---|---|
| Movement | Citizen 8204 automatic mechanical |
| Case | Stainless steel; 42 mm diameter, 12 mm thick |
| Weight | 94 g |
| Water resistance | 20 bar |
| Bezel and crown | Unidirectional rotating bezel; screw-down crown |
| Crystal | Listed as crystal glass by Citizen Europe |
| Strap | Black urethane; pin buckle; 20 mm lug width |
| Reserve | Roughly 40 hours; European fields give both 40 and 42 hours |
The official listing does not identify the crystal as sapphire or provide a clearly labelled lug-to-lug measurement. Its reserve fields also disagree slightly. For planning a rotation, the useful conclusion is unchanged: a full unworn weekend can outlast the stored power. No current official UK price was verified for this exact suffix.
The direct Seiko comparison
The Seiko Prospex SRPE93 is a meaningful comparison because Seiko identifies it as a 200 m diver. Its official UK listing showed £390 on 8 September 2026. It measures 45 mm across and 13.4 mm thick, weighs 124 g and uses a silicone strap with 22 mm lug spacing. Its 4R36 automatic movement has an approximately 41-hour reserve, hand winding and a stop-seconds function. The crystal is Hardlex.
That puts the Citizen 3 mm narrower, 1.4 mm thinner and 30 g lighter on the manufacturers’ figures. Those differences justify trying the NY0040 first if you find large divers cumbersome. They cannot establish that it will fit better: a curved case, strap stiffness and the way the lugs sit against your wrist can change the result.
The practical split is quite narrow once size is removed. Both offer a rotating bezel, a mechanical movement and a day-and-date display. Neither stated reserve removes the need to reset a watch left aside through a long weekend. Choose the Seiko if its broader case and dial presentation work better for you. Choose the Citizen if its proportions and unusual crown position make more sense in daily use.
What to check before paying
Try operating the crown with the watch off your wrist. The NY0040 places it low on the left side, so the setting routine differs from a conventional three o’clock crown. That arrangement can be appealing if your usual crown presses against your hand, but convenience depends on how you wear and handle the watch.
Turn the bezel and check whether its markings are easy for you to align with the minute hand. This is more useful than deciding from a photograph whether the bezel looks sufficiently purposeful. The same applies to the calendar: its information is useful only if you can read the window comfortably.
For a used example, request clear photographs of the dial, reference information and caseback. Ask about service history and any replacement crystal or bezel. A watch with a changed movement or aftermarket parts may still be enjoyable, but it needs to be priced and described as the watch it is today. A family name alone cannot establish originality.
Living with the automatic movement
The manual linked from Citizen’s product page explains manual winding as well as automatic winding. Wearing it helps replenish the mainspring; a short period on a quiet wrist need not restore a full reserve. After it stops, setting the calendar becomes part of getting ready to wear it.
Build that small task into the purchase decision. Someone who rotates watches for pleasure may enjoy it. Someone who wants to pick up a watch once a fortnight and leave immediately may find a light-powered Citizen a better match. The mechanical choice should earn its place through enjoyment, rather than an assumption that it is the more dependable option.
Buy the NY0040-09EC if you want a relatively restrained automatic diver and prefer its shape to the larger Turtle. Check the exact reference and the condition before treating any apparent saving as a bargain. Its strongest case is a useful combination of proportions and straightforward controls, supported by a design history with a clear purpose.
Image: AI-generated editorial illustration of the Citizen NY0040-09EC. Design details are approximate; this is not a product photograph.
