It was a promo card in the CoroCoro magazine that advertised the release of the Base set 5 days later. There is also a Jigglypuff. They are the 2 oldest cards of the TCG. (Carddass is not in the TCG). And the cool thing is that Pikachu wasn't supposed to be the icon of the license. Ultra underestimated card ! And Sugimori is an error that they corrected later (Kinebuchi was the artist), that's how we know that it's the one older than Base set.
by Ricoquin