The Guitars
I know very little about Kawai the company (you can find their homepage here), other than it is a Japanese company, founded in 1927 which continues to produce keyboard instruments and which produced guitars from the 1960s until the early 1980s.
Wikipedia includes all of 2 sentences on the guitar range (here).
I also know very little about the ranges of guitars that they produced, other than the KS range which was available in the UK in the late 1970s. Prior to the KS range, most Kawai guitars seem to have been produced and marketed under the "Teisco" name, a brand which is more associated with multi-pickup, multi-switch guitars which were fashionable in the 60s.
This site is focused on the KS range of guitars made by Kawai and sold under the Kawai brand in the late 70s and early 80s. It appears that Kawai withdrew from the guitar market, at least in Europe, sometime in the early 80s, although they did produce the "Moonsault" guitar in both the mid 80s, and then (as a reissue) sometime in the 90s. I know a lot less about the Moonsault than I'd like to know - so please make contact if you know more.
The KS range comprised of 3 distinct models - the KS-10, KS-11 and KS-12.
Each model had 2 variants, the "Junior" and "XL", and 2 finish options, which varied by model.
The main differences between the Junior and the XL were that the latter used a "Badass" bridge, and "Mighty Mite" humbucking pickups, whereas the Junior models had a separate bridge and tailpiece, and used "standard" humbucking pickups.
The range shared a number of design features. All were:
double cutaway body
twin humbuckers with individual tone and vol controls for each pickup
with a unique (?) for an electric guitar, open-headstock design.
The separate models then introduced various features relevant to that model.