Production numbers & timeframes: dive watches

This page is dedicated to my studies on production numbers and -timeframes of Seiko Vintage Dive watches. Model series included in the study cover the automatic 300 m models as well as the 'classic' 150 m divers (6217, 6105, 6306 and 6309).

The first part deals with the distribution of my current data set, then for the first time I will publish some results on absolute production numbers and eventually a timeline of the manufactured models.

Distribution of the data set

Caseback data were stored in the format of pictures with calibre, case, subcase, factory code, YYMM and serial number contained in the file name. Data were imported and analyzed with MS Excel. Data source for the divers watches: eBay (approx. 85 %) and various watch fora (approx. 15 %).

As of August12 2012, the archive contained a total of 1570 caseback pictures of divers watches, figures 1 and 2 show the distribution of the data set per movement (figure 1) and for movement/case/subcase combination (figure 2).
Figure 1


Figure 2


Absolute Production Numbers

This is the first time I try to publish some figures on the absolute production numbers of the series I study. At this stage, I can only present data on watches with the 6-digit serial numbering system, I have not yet found a way to interpret the 7-digit that makes sense to me. Furthermore, it must be clearly noted that the data in my archive are not yet at all sufficient to allow an accurate determination of absolute numbers. The data I will present are thus to be interpreted as ballpark numbers but in my opinion are (1) the best data available so far and (2) should give at least a good impression of which numbers we are dealing with beyond orders of magnitude.


Data for 6-digit watches are thus are based on the following assumptions:

 
  • Each case/subcase combination has an own serial number (e. g., separate serial numbers for 6309-7040 vs. -7049).
  • Serial numbers are reset once a month, first watch produced carries serial number YM0000
  • Each Factory code has an own serial number (if thus watches were produced in two different factories within the same month, both factories applied their own serial number)
  • All cases were built into actual watches
For the analysis of absolute production numbers, the dataset was thus evaluated for the maximum serial number per calibre/case/subcase/factory code/YM combination and all the maxima over the production timeframe were summed up. In case that a watch was produced in two different factories, the subsums for factory where then added up.

Results are summarized in table 1 and figure 3:
Table 1:
Figure 3


Production Timeframes

The evaluation of production timeframes was fairly staightforward, the dataset was analyzed for minimum and maximum YM combinations per model. The evaluation was only done on a case, but not subcase level (i. e., 6309-7040 and 7049 are evaluated together) in order not to clutter up the already busy graph.

Results are depicted in figure 4, the lines represent the production timeframe for each model, production start/end are indicated in in YYMM format.
Conclusion and Outlook:

This study gives a first impression about the absolute production numbers of Vintage Seiko divers watches. The data are however to be interpreted with care and to be assumed as the minimum: as further data become available, the numbers will definitely increase and become more accurate.

The data shown on production timeframes are assumed to be fairly accurate but might also slightly change with the addition of new study material.

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