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Seiko's 52 Stream was a family of high-end automatic watch movements from Seiko produced in the 1970's. Closely-related members of this 5200 family include the 5206, 5216, 5246 and 5256. The 5200 family was the basis for the 4S family of 1992-2013.
The 5200 family was introduced in 1970 as perhaps the last Seiko automatic movement of the classic period. It was designed and produced by Daini Seikosha, one of two different watch companies under the Seiko Group umbrella. As the transition to quartz began, many at Daini thought this would be their last chance to design an automatic movement, and competition between Daini and Suwa Seikosha led to aggressive engineering. The finished product was thoroughly modern, with up to date features like hacking, hand winding, integrated automatic winding, and a micro regulator.
The 52 Stream is comparable to Suwa's 56 Stream, introduced a few years earlier. Both were designed for mechanized mass production, though some members of the 5200 family were hand assembled and regulated.
The first member of the family was the 5206, introduced in 1970 in the Lord Matic. But it was the 1971 introduction of the King Seiko 52KS 5246 that made this movement famous. A modest upgrade came a year later with the 5216, which added a spring-loaded pawl to eliminate the risk of breakage if the date was changed around midnight. The line continued in use through the 1973 introduction of the 5256 but an industry shift to electronic watches meant the end of the line came in 1976.
Although it only operated at 28,800 A/h, Seiko classified this a “Hi-Beat” movement.
Because this was only the second bi-directional automatic winding movement ever produced by Seiko, it has some quirks. The reverse winding gear remains engaged when the date quickset is used, causing extra drag and causing concern for some users. The early 5206 version also suffers from a date pawl that can be broken if the date is set late at night, a common issue for many watch movements.
The 5200 family was resurrected in the 1990's as the high-end mechanical watch market rebounded. The result was the 4S15 and its derivatives.
The 5200 family operates at 28,800 vph, in keeping with the high-end Swiss competition.
The 5200 was produced in various quality standards, with a series of “Special” variants boasting better regulation for greater accuracy.
- Note that the 5206 and 5216 came in both 23- and 25-jewel variants. The main difference between these two is that the 5206 require one to wait for a “safe” time of day to set the date.
|5206A, 5216A||1970||Automatic||Hour, minute, seconds||Day and Date||None||23 or 25|
|5246A||1971||Day and Date||25|
|5256A||1973||Day and Date||25|