There are12 variation on a-581 watch case back. Since all case back (except the latest model) are compatible each other, so, unless you are the first hand owner of your A-581 and you should never be trusted you have a right case back.
Collector always has his own theory on verify the production dates of these case back and so am I..
Collector always has his own theory on verify the production dates of these case back and so am I..
# 1 - 1958~1960. The opening slot still exited. You can chase back the same slot design to their prototypes products on 1956 to 58, but with different diameter and engraving only.
#2 - 1960~1961. The slot disappeared and has changed to polygon shape flat bits (can only be opened by factory made case-wrench). It still carry the same case back pattern of 58~60 models (# 1)
#3 - 1961~1963. It has the same thickness of case#2 and also flatten in shape, except the whole engraved pattern has redesigned. It was only for chrome plated model.
#4 - 1961~1962. It carries the same pattern as #3. #3 & #4 were at the same production dates and #4 was only for the stainless steel case watch
#6 - 1962~1963 for stainless steel model. The fist engraved and stated ”Quan Gang(Stainless case & back)” case back in the whole Shanghai watch series.
#5 & #7 – 1963~1964; #5 was for stainless steel watch and #7 for chrome plated. Please note, starting from this lot of A-581 series has been changed to A581 officially.
#5 & #7 – 1963~1964; #5 was for stainless steel watch and #7 for chrome plated. Please note, starting from this lot of A-581 series has been changed to A581 officially.
There was another variation for #5,6,7 case back - with a serial number of 63xxxxxx marked on the other side of caseback. Nobody knows why, but it could firmly prove their production dates.
#8 & #9 – 1964~1965; #9 was for stainless steel watch and #8 for chrome plated. The are two difference screw diameter of #8 case back has been found, 29mm & 30mm. From 1958~1965, Shanghai Watch Factory product had hold the same 29mm inner screwed diameter case back of their products. Starting from1965, the whole production line had changed to 30mm.
#10& #11– 1965~1967; both 10 &11 were also for chrome plated watch. Please note, starting from 1965, A581 has been changed to mode 581 and also this is the end of the whole A-581 watch series production.
Since so many model 611, 623, SS1…had launched to the market during 1965~66, there were so many choice for buyers, so it might be the reason for Shanghai Factory terminated the 581 production.
#10& #11– 1965~1967; both 10 &11 were also for chrome plated watch. Please note, starting from 1965, A581 has been changed to mode 581 and also this is the end of the whole A-581 watch series production.
Since so many model 611, 623, SS1…had launched to the market during 1965~66, there were so many choice for buyers, so it might be the reason for Shanghai Factory terminated the 581 production.
#12 ….A -591…1959~60 case back.
If you are luck enough you could find a rare A-591 case back or even the rarest prototype case back!!
A - A-591 case back with prototype mark
B - A-591 case back with 3 prototype mark
C - A-581 case back with prototype mark
