Citizen KEI NK0051-51J Watch - Dark Grey Dial

Citizen KEI NK0051-51J Watch

The Citizen KEI NK0051-51J is an automatic from the KEI series, the line with which Citizen returns to essentials: watches of clean balance, with nothing superfluous, made to outlast a trend. KEI began as a project for the Japanese market. The brand already had sports models (Promaster), mechanical pieces with character (Series 8) and recognisable classics (Tsuyosa), but it lacked a neutral piece that was neither one nor the other. That is where KEI came from: a watch that adapts to the wrist and to the occasion without imposing a style. In this variant, the dial is dark grey, a tone that follows the line of the steel case and bracelet, but one step above it.

The case is steel, 38 mm in diameter and 10.9 mm thick, and weighs 134 g. The 38 mm is a size Citizen chose on purpose at a time when the market is returning to contained dimensions. The distance between the lugs has been shortened so that the watch sits well on the wrist and does not shift. The fitted bracelet is solid steel, not integrated, and closes with a deployant triple-folding clasp with pushers.

The dial is dark grey, with luminous hands and indices, and includes a date window at 3. The crystal is flat sapphire. The case back is transparent and screwed down, allowing the rotor and the movement to be seen in operation. Water resistance is 5 bar.

The movement is the 8310 calibre, automatic, the same as the latest Tsuyosa and Promaster models. The crown is pull-type, not screw-down, and is located at 3. Compared with the Tsuyosa, the position of the crown changes, not its function: it also has hacking seconds for precise setting.

Legibility has been worked on to the millimetre: the minute and seconds hands reach exactly to the scale, and the hour hand stays close to the indices, so the time can be read without effort, even in poor light.

The KEI series is not a Tsuyosa and not a pilot's watch: it is a dress automatic with a contained case, designed to accompany for years. Citizen describes it as a piece without adornment, focused on what is truly asked of a watch: that it reads well and feels comfortable. The NK0051-51J is the dark grey dial variant within a series that also offers silver-white, black, blue and silver with gold details.

The dark grey of this dial is not just another colour within the KEI series: it is the one that separates itself from the steel of the case and bracelet without breaking the line of the watch. The dial is one tone above the metal, and that makes it stand out against it without becoming a harsh contrast. Everything reads as a continuous metallic whole, but with the dial marking the focal point. It is the KEI for those who want a mechanical watch that shows on the wrist without giving up the see-through back or the steel bracelet.

Automatic 8310 Calibre 60-Hour Power Reserve 38 mm Dark Grey Dial Flat Sapphire

Why choose this watch?

60-hour power reserve

The 8310 calibre offers 60 hours of running time, compared with the 40 hours of entry-level automatics.

38 mm and 10.9 mm: contained case, short lugs

Citizen shortened the distance between the lugs so that the 38 mm case sits well on medium wrists without overhanging. The 10.9 mm thickness and 134 g keep it flat under a sleeve. It is not a watch of presence, it is a watch of proportion.

Dark grey dial: one tone above the steel

The grey of the dial blends with the steel of the case and bracelet, but one step above: it stands out against the metal without breaking the line of the watch. It is the most chameleon-like variant of the series, designed for those who want a mechanical watch that shows without drawing attention.

Legibility with hands extended to the scale

The minute and seconds hands reach exactly to the scale, and the hour hand sits close to the indices. It is a solution that prioritises clear reading over adornment. The result is a dial that reads without effort.

Frequently asked questions

Is the grey of the dial the same as the steel?

Not exactly. The dial is a dark grey, one tone above the steel of the case and bracelet. The contrast is subtle but enough for the dial to stand out against the metal without breaking the harmony of the whole. It is neither a light grey nor a black: it is a grey that separates itself from the steel just enough to mark the focal point.

Can the bracelet be replaced with a strap?

Yes. The bracelet is mounted on spring bars, not an integrated bracelet. It can be replaced with a 19 mm lug width strap. The only particularity is that the original clasp is a deployant triple-folding clasp with pushers, so a new strap will need its own clasp or a buckle.

Can it get wet, or does it only resist splashes?

Water resistance is 5 bar. It covers splashes, rain and hand washing, but not swimming or showering with the watch on. For aquatic use, a watch with higher resistance is advisable.

Does the 38 mm case work well on large wrists?

Citizen shortened the distance between the lugs on purpose so that the case does not overhang. It is a compact watch, designed for medium wrists. On large wrists it may sit tight, but the short lugs help it not to look small.