A serious collector will have dealings with the many descendants of the 38 caliber movement, like the 0920 QZ. The progeny was divided in SQ, QT, QR and QZ quartzes to keep track of quality and specs. 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. This one for instance was priced at 610 Euro in 1975.
