Pete,
You're right it was called "BlackJack". I've been wracking my brain trying to think of the Yoyo manufacturer that was so popular and finally the synapses fired....it was Duncan. They had the entire market cornered when I was a kid with butterfly yoyos, singing yoyos and even had the early ones that illuminated when they spun. Remember Tommy Smothers as "The Yoyo Man" on the Smothers Brothers Show. The guy is probably one of the best yoyoers in the country. I tried a few of his stunts when I was young and still can't think right from the concussions.
