Grand Seiko 4520-8000 in steel, hibeat 1968 June

Maker: Seiko
Model: Grand Seiko 4520-8000 hibeat
Year: 1968 June
Case Material: stainless steel
Case Dimensions: 36mm, thickness 9mm
Caliber: 4520A 25jewels, hibeat movement
Service history: June 2025. Currently running at +3.6 seconds/day.
Lug Width: 18mm
Bracelet/Strap: Handdn togo biege calf strap
Box/Papers: none
Caseback: Original GS gold medallion. comes with a clear case back 

The Grand Seiko 4520-8000 is a historically important timepiece produced by Daini Seikosha Kameido factory, a subsidiary of Hattori Watch Company (aka. Seiko). One of the standout features of the Grand Seiko 4520-8000 (and its date brother 4522) is its slim "grammar of design" case profile. At just 9mm thick, this watch is much thinner than many other mechanical watches of the era. The case famously was designed by Tanaka Taro, Seiko's first in house designer, and was introduced in the 44GS - also produced by the Kameido factory. Powering the Grand Seiko 4520-8000 is the high-quality 4520A caliber-developed in-house by Daini Seikosha and arguably the greatest movement made by Seiko, ever. Introduced in 1968, the Hi-Beat caliber 45 was used in both the King Seiko and Grand Seiko models, and is loved by Seiko enthusiasts around the world for its incredible accuracy. The 45 family of caliber's consists of the 4502A, 4500A, 4520A, 4522A, and the 4580. Hi-beat (that is a movement with 36000 bph) movements existed before 1968, most notably constructed by Girard-Perregaux and Suwa Seikosha, but the caliber 45 was designed by Daini Seikosha completely from scratch and in-house. The 45 family of movements represent the pinnacle of Japanese watchmaking achievement as its derivative competed in the 1968 Geneva watch competitions where it swept the mechanical watch category for accuracy beating out top Swiss watchmakers. 

The example offered here is an all-original Grand Seiko 4520-8000 in superb vintage condition. Based on our experience handling many 45GS pieces, the case appears unpolished, retaining its sharp Tanaka-designed facets and strong lines. The original white eggshell dial remains clean and vibrant, with only a few faint marks along the lower-left edge visible under magnification—not noticeable to the naked eye. The hands, crown, and signed caseback with its gold GS medallion are all original. The medallion has developed a pleasing patina. The patina can be easily removed with a polish but we've decided to leave it untouched. 

The crystal has been upgraded with a new-old-stock 45GS replacement. The watch has been recently serviced (June 2025) and is performing with excellent precision at +3.6 seconds per day—what you’d expect from a well-maintained high-beat Grand Seiko.

A clear caseback has been added to showcase the beautiful 4520A movement, while preserving the original medallion caseback. The watch is paired with a premium beige Togo calf leather strap handmade by our friends at Handdn.

Ships from Japan