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Elegance Collection
Automatic Mechanical GMT
SBGM257

A classic mechanical GMT, the "Moondrop" expresses
the beauty of dew drops gleaming in autumn moonlight.

SBGM257G

SBGM257

Elegance Collection

GBP 4,550.00

Dec. 2025 Release

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Features

In autumn, when the moon’s light fills the sky with its soft glow, drops of dew gleam in the light in a moment that captures the beauty of the season. The SBGM257 “Moondrop” expresses such a special moment with its textured blue dial. Thanks to its modern geometric spiral pattern, the dial changes in appearance based on the angle of the light, recalling how dew drops gleam in the moonlight. The intricate pattern imparts a refined sense of structure, a fitting complement to the Zaratsu-polished case and the high precision of the Caliber 9S66 GMT movement. Prized for its accuracy, beauty, and reliability, this movement enables the wearer to track two time zones simultaneously. The gold-colored GMT hand can be set to one’s home time or any time zone of one’s choosing. The local hour can be changed in one-hour increments when the crown is extended to the first click position, making time zone adjustments simple and intuitive. The power reserve is approximately three days.

Specifications

Exterior
Exterior: Stainless steel, Caseback: Stainless steel and sapphire crystal
Case back: See-through case back
Case back with 6 screws
Glass Material: Box shaped sapphire crystal
Glass Coating: Anti-reflective coating on inner surface
Case size: Diameter 39.5mm Lug-to-lug 46.9mm Thickness 14.1mm
Band width: 19mm
Band Material: Crocodile leather
Clasp type: Three-fold clasp with push button release
Movement
Caliber no.: 9S66 Instructions
Movement Type: Automatic with manual winding
Power reserve: Approx. 72 hours(3 days)
Mean daily rate: +5 to -3 seconds per day
  • Mean daily rate is a mean value of daily rates in a condition where the movement before assembly in a case is measured in six positions in a fixed manner under artificially controlled environment for 12 days.
Normal Usage Accuracy: +10 to -1 seconds per day
Functions
Water resistance: Splash Resistant
Magnetic resistance: 4,800 A/m
Weight: 92 g
Other details / Features:
  • 35 jewels
  • 24-hour hand (dual time display function)
  • Calendar-linked time difference adjustment function

Expressing a scene of autumnal beauty

With its textured spiral dial, the SBGM257 captures a moment when the seasons are especially felt in Shizukuishi, the place where Grand Seiko mechanical watches are made. The dial vividly recalls a time of year when moonlight is reflected by drops of dew in a delicate expression of autumnal beauty. A rich contrast results from the gold-colored GMT hand and the navy-blue textured dial.

Sophisticated and graceful design

Before the Grand Seiko Style was established, the very first Grand Seiko watch was born in 1960. Its spirit lives on in the case design of this model, which blends classic elegance with modern refinement. The watch’s round form presents a gentle silhouette from every angle. Though seemingly simple, the lugs feature an intricate slope that widens toward the tip, accentuating the distortion-free mirror surface and delicate ridgelines created through Zaratsu polishing. The brilliant shine of the case, created by our craftspeople, adds a touch of tension to the classic aesthetic, resulting in a sophisticated and graceful design.
Watch finder

The three movements at the heart of Grand Seiko

9SMechanical

One of the world's foremost mechanical movements, the culmination of high-precision micro-engineering and the attention to detail of Grand Seiko's expert watchmakers.

9RSpring Drive

Spring Drive’s unique movement technology generates power through a mainspring like other mechanical watches but combines this with the Tri-synchro Regulator for extraordinary precision.

9F Quartz

The ultimate quartz movement. Caliber 9F incorporates several unique technologies that raise the performance of quartz to the high standards of Grand Seiko.