To my understanding there had been quite some regional models from Kuwahara, often influenced by the bigger retailers like Villiger in central Europe.
The catalogs in the Archive are the ones from Villiger.
So also the 1988-1993 catalogs on this page
https://kuwahara-family.brieger.blog/kuwahara-kataloge/
Yours is quite different.
But there are other similar Kuwahara Bikes like yours. e.g. this one
https://www.ebay.com/itm/174314950279
It seems that for Spain they had a different portfolio, maybe managed directly from Kuwahara out of Osaka and not via a central distributor like Villiger?
This test is from the spanish Bicisport Guia 1990 buyers guide
View attachment 873927
and the full portfolio, with model names completely different to what was sold in other EU countries.
View attachment 873928
There is no Omega mentioned, just your's seem to be a bit older (do i recognize a XT 730 with 6speed thumb shifter?)