Back in 1968 during the last of the Chronometre competitions that were known as the “Accuracy Observatory Trials” at Neuchatel in Switzerland, the watches from Seiko were judged to have the most accurate mechanical calibres beating all entries from other manufactures. As well as entering competitions Seiko manufactured some astonishingly accurate watches for general sale during those days under their Grand Seiko and King Seiko lines, these were labelled (depending on the line) as Very Fine Adjusted (VFA), Superior Chronometer or just Chronometer. As accurate as these were even their “plain” (if such a term can be used) calibers were remarkable timekeepers. One of the big drivers behind all this increasing accuracy was that Seiko had two manufacturing plants, Suwa and Daini, that were set up in competition with each other to try and push the boundaries of technical and manufacturing development. The example featured in this article is a King Seiko 4402-8000 manufactured in May 1968, right at the time Seiko was winning the Chronometre competitions and striving to make the most accurate watches they could. The watch is powered by the calibre 4402a which is a hand wind, hacking, 25 jewel, 18,000bph movement. It’s a fabulous example which appears to be on it’s original stainless steel bracelet, again which is in fabulous condition.
The caseback is engraved in the horseshoe style with a gold medallion in the centre. These medallions were found on various Grand and King Seikos and are made from a solid gold disc bonded to the stainless steel caseback. They featured a whole myriad of logos dependant on the watch they were destined for, from the lion of the Grand Seikos, right through to the plain Seiko and Daini symbol seen here.
With the caseback removed you can see the beautiful hand wind movement with its “tadpole” fine regulation lever adjustment. These calibres also had an individual serial number engraved on the train bridge.
Now the movement is out you can see the classicly simple dial with its set of beveled dauphine style hands. The watch borrowed a lot from the design ethos of the Grand Seikos introduced by Taro Tanaka which comprised of lots of flat highly polished lines and surfaces to reflect the light.
Below the dial the calendar side is relatively uncomplicated.
The amount of shock protection used in this calibre is probably over the top, there’s the usual diashock jewels on the top and bottom balance piviots, but there is also diafix shock protection on the upper and lower third and escape wheel pinions and on the lower fourth/seconds wheel pinion!
Another nice feature of this calibre is the date change wheels jewelled post.
With the calendar side stripped the train side can be started, note the large diameter balance wheel.
You can see a little bit of perlage on the area around the outside edge of the balance wheel, just enough to look nice when assembled.
A little further in and you can see the hacking lever which operates on the seconds wheel.
Another nice touch is the fully jewelled barrel.
Enough shock protection for you sir?
The movement was soon stripped ready for cleaning and inspection.
With no issues found the rebuild could begin with the mainspring back in its barrel.
The train starting to come together.
The barrel bridge is back on in this shot.
All those diafix caps and springs are refitted and we’re ready for the balance assembly now.
It’s at this point I usually wind the barrel up and roughly adjust the regulation and do any mainspring adjustments necessary. With all the earlier talk of the accuracy of these watches it’s testament to their build quality and longevity that results like this can still be acheived after 47 years. This shot was taken after half an hours running on the timegrapher.
The calendar side assembly is under way here.
Ready for the top plate.
The movement spacer was secured by a couple of mismatched screws so they were replaced with a matching set.
The dial and handset refitted.
The movement recased ready for closing.
And here she is, ready for a few more years sterling service. These watches seem small by todays standards at 35mm diameter but dont let that fool you, they actually seem a lot larger on the wrist due to the large dial and narrow bezel. This is one of my favourite vintage Seikos, simply lovely.