View source for Seiko 35

'''Cal. 35 SQ''' (also called '''Cal. 35A''') was the first [[quartz]] movement from [[Seiko]] and the first production quartz movement sold to the public. It was produced from [[1967]], offered for sale on December 25, [[1969]], and continued in production for a year or so after.

==History==

[[Seiko]] was quietly racing to develop a [[quartz watch]] movement in the 1960s, and delivered their first Cal. 35 movement to the [[Neuchatel Observatory]] in late [[1967]], just a few months after the [[CEH]] delivered their [[Beta 21|"Beta" quartz movement prototypes]]. Seiko's movements were not thermocompensated so they performed poorer than the Swiss movements, but they incorporated modern design touches including a [[stepper motor]] rather than the [[vibration motor]] used by the Beta movements. Cal. 35 was a product of [[Suwa Seikosha]] and had an 8,192 Hz quartz crystal. The [[integrated circuit]] used to count quartz vibrations was produced by [[Intersil]] in the USA.

Seiko offered Cal. 35 SQ for sale in the [[Seiko Astron]] watch on Christmas Day, [[1969]]. This marked the first quartz watch available for sale, though [[Longines]] had announced their [[Longines Ultra-Quartz|Ultra-Quartz]] five months earlier. Seiko claimed to have sold about 100 examples in the first month, and delivered perhaps 1,500-1,800 examples total in a one-year period. The first deliveries took place in January [[1970]], well before any Swiss quartz watch.

The initial Astron watches used Cal. 35 SQ, but a [[date]] complication was soon added and the crystal was upgraded to 16,384 MHz. Cal. 35 SQC (with date) was somewhat more common later in the year. Both movements are called Cal. 35A officially.

Seiko introduced [[Seiko 36|Cal. 3600]] in [[1970]] as well, but neither was produced in large volumes. Suwa's next quartz movement, [[Seiko 38|Cal. 38 SQW]] was more production-ready and went on sale in late [[1971]]. The Cal. 38 series marked the first true production quartz watch from Seiko.

{{WD|
'''Description:'''
:[[Quartz]] movement with [[stepper motor]]

'''Functions:'''
:Hours, minutes, central seconds
:Optional [[date]]

'''Data:'''
:7 [[jewels]]
:8,192 Hz or 16,384 Hz
:[[Integrated circuit]] with 76 transistors and 29 capacitors
:[[Stepper motor]]

'''Production period:'''
:[[1967]]-[[1971]]
:Successor: [[Seiko 38|Seiko 38 SQW]]
}}

==External Links==
* [https://reference.grail-watch.com/family/seiko-35/ Suwa Seikosha 35 Quartz Stream]

[[Category:Movements]]
[[Category:Quartz movements]]
[[Category:Seiko calibres|35]]
[[Category:Seiko quartz calibres|35]]