In short, pointed and with the chances given by hindsight: The History of GrandSeiko.

• GrandSeiko started in 1960 with the refJ14070; basically just one watch which was oriented, influenced and inspired (some say "copied"?) from the back-then most relevant and highest-quality Japanese watch, the Citizen Super Deluxe (*klikk); now it is called GrandSeiko "First", the refJ14070 but when it was introduced it was just the GrandSeiko, as first makes just sense when there is a second or a series and I have serious doubts this was planned in 1960; instead there were several of such aristocratic labels and model-names, all created by the two competing arms (Suwa & Daini) of the Seiko Corp.: Lord, King, Cronos, Crown, Marvel & the Grand Seiko;
• these were introduced and there was a lot of trial and error with the result that the GrandSeiko was a great success and so...
• in 1964 with the second Grand Seiko (ref43999) it was established as a quality-label: SEIKO-logo (!) and below the stamp GrandSeiko / GS -- something that went on, until it didnt: until GrandSeiko was switched-off in the mid '70s;
• GrandSeiko was intended to reach and compete and eventually exceed the best mechanical watches in the world back then, the Swiss (see here: "Grand Seiko was born with the determination to create watches of high precision and quality that could compete on the world stage."); and that goal (to compete at par) was reached in 1968 / 1969 with the automatic cal61 and the manual cal45;
• even more: the GS Very Fine Adjusted (V.F.A.) exceeded mechanical Swiss watches in accuracy with a deviation of just 5 seconds per day or 1 minute per month (-2 to +2s, *klikk) and -- most important -- Seiko understood that they reached the end-point and excellence in mechanical watchmaking with this; that is why there was never a mechanical Seiko Superior or any other GrandSeiko-topping label for mechanical watches from Seiko;
• and there are good reasons to assume Seiko was correct: Rolex uses the Superlative Chronometer-standard (also a var of 5spd aka 1 minute per month) since 2015 as well; and the Omega Master Certification translates to the same accuracy, today; so, we are where we had been before in mechanical watchmaking during the last five decades (again here: *klikk) and with this understanding Seiko closed the GS-book in 1974 and focused on the electronic / quartz watches, exclusively;
• notabene: there were "Grand"-marked quartz-watches as well -- Seiko GrandQuartz -- but they were topped by the "Superior"-line;
• in the mid 1970s Seikos understanding was obviously that electronic watches will be THE (!) way to go into the future; and although their assumption that peak-mech was reached, seems correct, the former assumption (quartz-only) was wrong as the Swiss proved: it was not THE way to go into the future, it was ONE (!) way to go into the future -- the other was mechanical and it was Seiko itself that developed a third, a kybernetik way in between both realms with its Spring Drive;
• to make a mistake is not a problem, if you correct it; and so Seiko did an adjustment to their view: just in 1988 they re-introduced the GrandSeiko highest-quality badge, proving that the Seiko bearing it, was done to the highest standards and they did so for the electronic (quartz, cal9581 & cal9587) in 1988 and ten years later (1998) for mechanical watches as well with the cal9S; the hybrid SpringDrive arrived just a year later but was not a GS until 2004 -- keep that in mind, we will come back to that strategy of Seiko later;
• we see here what it was before: a highest-quality Seiko (now either mechanical or electronic) became a GrandSeiko, marked with the GS-symbol next to the SEIKO-application;
• that changed in 2017, when Seiko announced the split and formation of a standalone brand GrandSeiko -- so what started as a single watch, and then was a quality-stamp most of the time is now a full standalone brand offering not only mechanical but also electronic and even watches in between (SpringDrive); instead of deciding for one or the other -- mechanical || electronic -- Seiko went the confucian-way: showing respect for and reaching excellence in BOTH realms and further connecting them by a hybrid-movement in between; what before marked the upper-class watches became a brand: GrandSeiko;
• And why? Because the wide variety of models, price- & quality-levels in the Seiko Corp required such a stamp (and now brand) to allow the easy recognition of a more expensive and higher quality product; to not mistake it for something cheaper and mid-level;
• this could be used as a rule-of-thumb, a heuristic BUT: there are a couple of interesting exceptions from this simple GS-rule -- there are the GrandSeikos and there are the GreatestSeikos and both are not always the same, but that will be pointed out later;

Overall, there is a lot more to see and find in the details and in the history of the Seiko Corp and we will open that in the next publications.

Our Seikos et. al. (ie. Japanese watches) here: *klikk.