Manufacturer : Shanghai Watch Factory (上海手表厂）
Year of Production: 1964
Case Diameter :
Weight w/o strap: g
Movement Model : A581 (17 jewels)
Type : Hand Wind
Watches in Shanghai 581 series are among the most popular items for vintage collectors.There were three models in the series: A581, A-581 and 581 produced between 1958 and 1967.
The following parts of the post are abstracts from the detailed and extensive write up from micmicmor website. According to the website, the main criteria in authenticating a model in the series, other than the obvious "A581", "A-581" and "581" inscription on the caseback, are:
- it has no anti-shock unit in the movement;
- it has metal movement holder ring with 5 holders [see post here];
- both ratchet and crown wheels should be flat on edge [see post here];
- the hour and minute hands are flat (there should be no camber from centre to the tip of the hands) [see post here];
- the second hand should have narrow pointer or no pointer at all [see post here];and
- it has a hemisphere signed crown [see post here]
Ascertaining the year of production of this piece:
- the caseback is of type #8 in this post of micmicmor website and accordingly it should be a product between 1964 and 1965;
- The Zuan (jewel) in Chinese had been in simple form "占" until about 1964 it was changed to more complicated character "钻“ (see this post) - this watch has "占" on the dial;
- the screw compensated balance was improved and became unscrewed in about 1964 - the watch has a screw compensated balance wheel which should be among the last few batches;
- It has the date code of 6402A under the balance wheel which means the first batch of production in the month of February in 1964 (the first 2 digits are year , the latter 2 digits represent month and the alphabet at the end means the batch of production in that month [see post here])
The date code is not contradictory to the other three points and therefore it is certainly a 1964 product, the oldest watch that I have acquired so far.
On the caseback, there are "上海手表厂" (Shanghai Watch Factory), "SHANGHAI", "A581", "半钢" (half stanless steel) and "BAN GANG" (the pinyin of 半钢). Half stainless steel means save only the caseback which is in stainless steel the rest of the case are chrome plated.
More pictures are here:
1. the watch;