Grand Seiko 5646-7010, Sunburst Dial, Cal. 5646A Automatic, Serviced, Manufactured in 1971 (Showa 46)

This is a 1971 Grand Seiko "5646-7010".

The "56 Grand Seiko" is the final series that capped off the history of mechanical Grand Seikos.
It is a highly practical, luxury mechanical watch that achieves a thin, compact, and lightweight design while featuring a high-precision, high-beat automatic movement.

The sophisticated GS case and the simple yet sharp dial design exude the distinctively sharp and dignified aura unique to vintage Seikos.

The "GS Case" employed here is the classic design of the "Seiko Style," composed of flat surfaces and secondary curved surfaces, which has been passed down through generations of top-tier Grand Seiko models.
The sharp edge lines, unique to the original, remain beautifully intact, allowing you to enjoy the proportions of that era.
The case back is a screw-back type and features the precious gold GS medallion.

The dial is finished with a delicate sunray pattern, revealing an elegant appearance that shifts from silver to a warm champagne gold depending on the angle and how the light hits it.

With a day-date (Japanese/English) display, a second-hand stop function (hacking), and manual winding capabilities, it boasts high practicality that fits well with a modern lifestyle.

Condition

This watch has undergone a complete overhaul (disassembly and cleaning) and exterior refinishing.

The "date/day quick-change function," which is a delicate point for the 56-series movement, also operates normally.

The crystal is clear and pristine without any noticeable scratches.
There are tiny, pinpoint-sized spots (due to aging) on the dial at the 5 o'clock and 11 o'clock positions, but considering the production year (1971), these do not detract from the overall aesthetic or the beauty of the sunray finish, and the watch remains in excellent condition.

The strap has been replaced with a brand-new genuine Seiko leather strap, so you can wear it comfortably immediately upon arrival.

The crown is also the original genuine piece with the "GS logo."
The gold GS medallion on the case back has no noticeable scratches, peeling, or corrosion, and remains in beautiful condition with its original three-dimensional texture intact.

※As this is a vintage watch many years past its production date, it is not waterproof.
Please refrain from wearing it on rainy days or during hot days when you are prone to sweating.
Additionally, please be careful to avoid "strong impacts" and "magnetic fields (such as from smartphones or PCs)," which are the natural enemies of mechanical watches, and handle it with care.

Operation Instructions

Manual Winding: With the crown in the normal position, rotate it upwards (clockwise).

Setting the Time: Pull the crown out to the second click and rotate it downwards (counter-clockwise).

※The second hand stops when the crown is pulled out to the second click (hacking function).

Quick Date Change: Pull the crown out to the first click and rotate it downwards.
Quick Day Change: Pull the crown out to the first click and rotate it upwards (switches in the order of English → Japanese).

[Important] Attempting to use the quick-change function while the watch hands are pointing between "8:00 PM and 4:00 AM" (the prohibited time for calendar adjustment) may damage internal parts and cause malfunctions.
To perform the quick-change safely, please be sure to set the time to "around 6 o'clock" before adjusting the calendar.