​Produced in September 1968 this is a beautiful example of the 4520-8000. The 45GS series was the second​ ​and final​ ​series to be manufactured by the Daini Seikosha company. ​From its release in 1968 it was m​anufactured until around 1973. The 800​0​ case is a solid structure and ​has​ typical “Grammar of Design”​ features.​ Equipped with Cal.4520, a high-beat hand-wound movement with 36000 vibrations, which is acclaimed to be the masterpiece of Seiko mechanical watches.