Within the world of vintage watches, Grand Seiko – like this full-serviced 1969 GS 4522-7000 Chronometer mechanical dress watch here, on a vintage new-old stock Japanese Bambi stainless-steel bracelet – with its distinctive "Grammar of Design," inhabits the top of the food chain, simple as that.
 
Grand Seiko watches were simply the most painstakingly designed and exquisite watches made by Seiko, produced by both the Dani and Suwa factories, including the 45GS Hi-Beat line here.  Grand Seiko’s 45GS series holds the position of the second, and final, series to be manufactured by the Daini Seikosha division of Seiko.
 
Make no mistake, Grand Seiko then and now marks the very best Seiko has to offer, easily on par with the vast majority of what Switzerland has to offer by way of competition.  And the 4520 represents one of the highest achievements of Grand Seiko – namely, creating one of the best watches on the planet.  Period.
 
In 1968 – the year before the example here - Seiko debuted the 45GS, only one year after Seiko brought out the inaugural Grand Seiko, the iconic 44GS, which revealed to the world its legendary “Grammar of Design” design by Seiko prodigy Taro Tanaka.  
 
Like the 44GS, the 45GS was produced by Daini Seikosha rather than peer Seiko competitor Suwa Seikosha, with the 45GS remaining in production until at least 1973.  Regardless, the 45GS shares a close visual relationship with the 44GS, easily revealing Tanaka as their architect.  
 
As noted by Hodinkee, “The Grand Seiko 45GS is a horological treasure hidden in plain sight. It combines the best of the Japanese company's technical bona fides while, in some models, beautifully reflecting Taro Tanaka's "Grammar of Design" ideals.”
 
Speaking of Grand Seiko design, in the early 1960s, Seiko’s Tanaka created a set of design principles he called The Grammar of Design.  In 1962, Tanaka noticed Swiss watches "sparkled brilliantly" and realized the design of high-end Seiko watches could be radically improved through the implementation of "flat and conical surfaces perfectly smooth and free of distortion." 
 
Tanaka’s Grammar of Design was implemented in Grand Seiko and King Seiko lines from 1967 and made these lines instantly recognizable as status symbols in the hierarchical Japanese business world of the 1960s and 1970s.  Tanaka’s rules would go on to fundamentally change Seiko’s design language. All surfaces and angles of the case, dial, indices and hands had to be flat and geometrically perfect to best reflect light. 
 
Following this aesthetic, bezels were to be simple two-dimensional faceted curves.  And third, no visual distortion from any angle was allowed, and all cases and dials had to be mirror-finished.  In “A Journey in Time: The Remarkable Story of Seiko,” Tanaka’s approach to the new style is described as follows:

“He started by creating cases and dials that had a perfectly flat surface, with two-dimensional curves on the bezel as a secondary feature.  Three-dimensional curves were not used, as a general rule.  He also decided that all distortion should be eliminated from the dial, too, so that it could be finished with a mirror surface.  This formed the basis for the new Seiko style.”
 
For a brief period in the late 1960’s and early 1970’s, some Seiko’s were certified chronometers by Bureaux officiels de contrôle de la marche des montres (precursor to COSC).  Seiko's history with the Swiss official chronometer rating is an interesting one, from Seiko's first participation in 1963 to its entry of the 45 calibre here in 1968.
 
Seiko nearly always placed rather well vis-a-vis its Swiss competition - almost certainly to the embarrassment of the Swiss.  When the successor to the chronometer contest was established, the COSC standard, the Swiss made the odd decision that "all parts used to build the movement must be made within Europe” ... jealous much?
 
Seiko would eventually eschew the Swiss-based chronometer certification in favor of their own, more stringent, standard, thusly beating the Swiss at their own game.  And Seiko would go on to be the first to invent the automatic movement (beating the Swiss, again)...but that’s another story.
 
This Grand Seiko comes on a NOS Japanese Bambi stainless-steel bracelet, and with a black and red nylon strap, rugged travel case, and springbar tool.