Saturday, October 22, 2011

1964 Cal 430 to 5722 Second Generation Grand Seiko Chronometer transition

 By way of introduction, these "second generation" Grand Seiko chronometers were preceded by cal. 3180 "first generation Grand Seiko". The 43999 has the caliber 430 (with "tadpole" regulation) and is occasionally termed 43GS, while the 57GS have the otherwise identical 5722A (tadpole) or the 5722B ("rack & pinion" regulation) caliber. Both are very similar to the original cal 3180 of the first GS.  My review of the cal. 430 Chronometer Grand Seiko can be seen at the Seiko and Citzen Watch forum

With respect to their crowns, a rule-of-thumb allowing the quick identification of otherwise essentially identical pieces is that the 43999 has a coarse-knurled crown, similar to that of the cal. 3180 "first generation Grand Seiko":

Source: Stefan Molle,

while the 5722 has the fine-knurled crown:


Both the 43999 and 5722 version of the second GS have the "W SEIKO" imprint on the crown. What is uncertain is whether there was a transitional period where 43999s had a fine-knurled crown, or whether these crowns where subsequently fitted during repair and maintenance.

The following indications suggest that there was indeed a transition period:

Exhibit 1: Antiquorum's recent auction of an early (1965) 5722 with a coarse-knurled crown:


Not exactly conclusive, but next we have:

Exhibit 2: 43999 paperwork, and what we must assume is the associated 43999, with fine-knurled crown.

Source: uhm, not sure, but seem to remember it was cached from Rakuten.

and finally,

Exhibit 3: From the "Vintage Seiko GS Chronometer Crown Liner 5722 5719 BOOK" what appears to be a cal.430 (=43999) judging from the short three-cifer caliber number on the movement, apparently a 1964 as far as I can make out from the case back, with a fine-knurled crown:

Source: eBay auction

Accordingly, it can be assumed to be correct to fit the fine-knurled crown (part number 55W31NS) to both the 43999 as well as the 5722 caliber second generation Grand Seiko chronometers, while maintaining originality.

Finally, part number 55W31NS is correct for the following watches:

  1. Grand Seiko Chronometer models 5722, 43999
  2. King Seiko Chronometer models 4400-9990, 4420-9920, 44999

1 comment:

  1. Dear Mr Harry!

    I want to buy the crown as your Photo ( W Seiko )
    Do you sell it?