Daini Seikosha produced just one 36,000 A/h “Hi-Beat” movement, the 4500 series of 1968-1974. These were used in high-end King Seiko and Grand Seiko watches in the 1960's and 1970's.
The 4500 family was introduced in 1968 to replace Daini's 4400 calibre. It appeared in the King Seiko 45KS and Grand Seiko 45GS models. Thanks to the “Hi-Beat” accuracy of the 4500 calibre, the 4420 was no longer needed. The date function featured an “instant change” mechanism.
In 1969, Seiko introduced V.F.A. (“Very Fine Adjusted”) versions of the 45GS, with monthly precision of +- 1 minute.
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