I also think it's Japanese. There were a bunch of factories back in the 60's and 70's that made guitars like yours. Collectively they were referred to as Teisco guitars, but there were many other brands and different styles abound. Many were sold through department stores with or without branding on the headstock. I have one with a chrome pickguard like yours that was made with the Kawaii label, and have others with no label. Some are completely made of laminated materials, and some are completely solid, with all variations under the sun. They appeared to have almost resellable value before the lending disaster, but now are once again very good guitars for trying all sorts of modifications. (I did my first fret job on one.)
For myself, I like the low impedance pick ups, but I use heavier strings than you're working with.
Ry Cooder, David Lindley, and probably many others have used these guitars very successfully for playing slide parts on.
One thing you might do is search on ebay for Teisco guitars, and see if you find one like yours that has more information about it. There's also quite a few websites about these guits. Good luck!!