Seiko Grand Seiko 'Serviced' 5646-8000 (1972)

Now available at auction from Second Vintage Presented here is a highly sought-after vintage Grand Seiko, distinguished by an exceptionally sharp tonneau case that preserves its original factory geometry and brushed finishes. Featuring a stunning grey vertically brushed dial in pristine condition and an intact, crisp gold GS medallion on the caseback, this 5646-8000 offers remarkable cosmetic preservation for discerning collectors. Brand: Seiko Model: Grand Seiko Reference Number: 5646-8000 Serial Number: 270313 Movement: Automatic caliber 5646A Dial: Grey vertically brushed texture with applied silver-tone indices Case Size: 37 mm (excluding the crown) Case Material: Stainless Steel Production Year: 1972 Condition: Excellent vintage condition. Movement serviced on 21 July 2026. Timegrapher: -4-7s/day, performing remarkably well. Dial and Hands The pristine and dynamic dial features a clean, highly legible grey vertically brushed texture. It is a well-documented collector fact that examples of the 5646-8000 originally featuring blue dials are known to fade completely to this striking grey over time. Applied silver-tone indices with black inserts are bright and free of corrosion, perfectly matched by the clean silver-tone baton hands with black central stripes. The printed text remains crisp and fully intact. Under extreme macro inspection, only microscopic dust or faint oxidation is visible on the hands, with no bending or material degradation. The dial is completely free of visible spotting, staining, or moisture damage, and displays a highly desirable English and Kanji day wheel. Case and Crystal The angular tonneau geometry is exceptionally well preserved, presenting sharp, crisp edges that define the character of this timepiece. The original brushed finish on the top surfaces contrasts cleanly with the polished flanks. Wear is limited to light superficial scratches and handling marks consistent with careful use, with no significant dents or deep dings visible. The polished fixed bezel ring is clean, showing only minor hairline scratches, and sits securely flush against the case. The clearly signed GS crown features sharp, well-defined knurling and sits neatly against the case flank. Turning the watch over reveals an intact and crisp gold GS medallion on the caseback. The flat crystal is clear, maintaining an intact beveled edge with no significant scratches, chips, or crazing visible. Movement Powering the watch is the chronometer-grade Seiko caliber 5646A, a 25-jewel automatic movement adjusted to five positions and temperature. The movement is visually very clean, displaying no signs of corrosion or moisture intrusion. The rotor and bridges show bright, intact finishing, and the screw heads appear unmarred. Recording -4-7s/day on the timegrapher, the caliber is exhibiting remarkable accuracy and consistency, performing brilliantly for a vintage timepiece. The movement was serviced on 21 July 2026. Strap The watch is fitted with a sturdy, period correct stainless steel block-link bracelet that suits the tonneau case geometry beautifully. The bracelet shows moderate surface scratches and normal wear, accommodating a maximum wrist size of 18 cm. Condition Excellent vintage condition. The movement was serviced on 21 July 2026 and, supported by the recorded timegrapher result, is performing very strongly. The watch remains in remarkable cosmetic standing, highlighted by a flawless dial and exceptionally sharp, unpolished case lines. The bracelet exhibits moderate, honest wear while remaining highly presentable. Dimensions The case measures 37 mm, excluding the crown. Remarks This Grand Seiko is a compelling acquisition due to its pristine dial and exceptionally sharp case geometry. The presence of the desirable English and Kanji day wheel, paired with the chronometer-grade 5646A Hi-Beat automatic movement, makes this a standout example for any collector of classic Japanese horology. History The 56GS series was produced by Seiko's Suwa factory from mid-to-late 1970 until early 1976. These timepieces represent a significant era in Japanese watchmaking, marking the final Grand Seiko models produced before the brand's temporary discontinuation. Today, finding examples that retain such sharp case lines and flawless dials is becoming increasingly difficult, making well-preserved pieces highly prized among enthusiasts. / Second Vintage SKU: SEI-SAH-0002