I did a post the other day about a promo card for a set that BBM did for the Giants that was distributed to subscribers of the Yomiuri Shimbun newspaper in 1999. I don't know a whole lot about that particular set but I do have a similar set that BBM did in 2000.
This set was distributed to the newspaper subscribers in six four card packs that were labelled Series I, Series II, etc up to Series IV. Each pack for each Series contained the same four cards (i.e, Series I contained cards 01-04, Series II contained 05-08, etc) although there was the possibility of parallel cards.
Like the 1999 set, the 2000 set was only Giants players. Series I through III and V and VI contained the "regular" cards in the set. One card in each Series had two possible parallel versions - a "blue silver" version (one in every three packs) and a "gold" version (one in every 10 packs).