Its a rear wheel off a Group-5 Super Silhouette race car - a racing series that ran in Japan between 1979 and 1984. These wild over-spoilered and over-powered race cars ran an assortment of awesome staggered BBS/Rays/Impul/SSR wheels - 16" on the front, and nineteen by fifteen inch on the rear!
I'm almost certain this wheel is off the back of the Tomica DR30 at some point; after the gold mesh it had ~1982, and before the rear wheels that are on the car currently were added.
..a world of stepping..
Its seriously hard to show just how huge this thing is - on its own it just looks like a wide wheel.. as if it were a 14x10 or something..
..Put it beside something else for reference, and bam.. it makes this 15x7.5" (+20) reverse mesh look like a space-saver!
Whats crazy is that this is still a bloody big wheel today; but in an era when near everything ran 14's and 15's, and 15x6.5" aftermarket wheels were standard fare; this thing must have been absurd!
I seriously love it.
(If anyone has a better Idea what this could be off, let me know!)