Sorry for the stupid question, I’m not as well versed in Japanese…
So many Japanese artworks that didn’t make it to US sets, were released as WOTC black star promos?
Did Japan have their own version of black star promos? are they just called Japanese Promos? or is there a specific name for the subset of vintage promos in the WOTC timeframe?
The original Japanese versions were released in a big variety of ways, over the span of many years. There are also many Japanese promos that didn’t get an English release at all, neither as promo nor set card.
If you go to Bulbapedia’s WOTC Black Star Promos list you can click on the individual cards and find their origin story under “Release Information”.
Alternatively, you can go to Bulbapedia’s Unnumbered Promotional cards list, where you’ll find both the originals of the Black Star Promos, as well as Japanese exclusives. This is a very valuable resource that includes many of the most interesting cards of the golden era.
Edit: fixed the second link.
They did not have a numbered set, it was quite scattered through all different magazines and other promo distributors. The closest to the english promo set you will get is probably unnumbered promos for pre 2001. This encompasses all of the promos in this timeframe. I personally would go by different promo sets, 1 corocoro set, 1 ana set, 1 neo premium file set, a cd set. This is a lot more cohesive imo.