Seiko Quartz QZ 0923-5000 (Sold)
Model: Quartz QZ
Reference: 0923 5000
Movement: Quartz at 15 spm Seconds PM
Case: 35x42x11mm without crown
A serious collector will have dealings with the 38 caliber movement and the other early quartzes of the seventies, like the 0923 QZ. These movements were divided in the SQ, QT, QR and QZ quartzes. They were the JDM (Japanese Domestic Market) watches made around 1971-75, while the export models were mostly labelled SQ 3003 (QT), SQ 2002 (QR) and SQ 4004 (QZ).
The highest quality and the most expensive of these quartzes were the SQ & QT with tighter specifications - 15s as compared to QR's 20. Only then came the QR and finally (much later in time as well) the QZ. But remember, at this time there were no cheap quartzes so even the "lower grade" QZ was more expensive than the average mechanical watch.
We are not done here however, and it does not get any easier as the 38 QZ descendant is introduced finally in 1975 with the 09 series with a 15/20spm specification.
In hindsight, there never was a model year where all these designations existed at the same time, but it is evident that some SQ's are better and more expensive than both the QT and QR. The cheapest QR of course was more expensive than the QZ at introduction but this compares 1971 against 1975 where there probably has been significant price erosion for quartz watches.