Grand Seiko 4520-8000 hibeat in steel from 1968 June

Maker: Seiko
Model: Grand Seiko 4520-8000 hibeat
Year: 1968 June
Case Serial: 861051
Case Material: stainless steel
Case Dimensions: 36mm, thickness 9mm
Caliber: 4520A 25jewels
Service history: November 2025. Currently running at +5.1 seconds/day.
Lug Width: 18mm
Bracelet/Strap: Handdn high quality calf beige togo
Box/Papers: none

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 first introduced used 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. 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 Swiss watchmakers.

This specific example is an all original 4520-8000 Grand Seiko. Based on our experience handling many 45GS's in the past, the case on this example likely has never been polished. It retains its beautiful Tanaka grammar of design profile. As can be expected from a watch of this age, there are light scratches on the case and bezel but nothing major. The original silver/white dial is in very clean condition with no major blemishes or discoloration. The crystal was replaced with a Seiko new old stock hardlex crystal for the 45GS . The handset and crown are all original and is in great condition. The case-back comes with its original gold GS medallion which is in overall excellent condition. The movement has  been serviced by our watchmaker and is running well at an excellent +5.1 seconds / day.

Ships from Japan