Anyone who knows me well, knows I love my giant Gorillas. King Kong is a personal favourite and I often cite it as my all time numero uno movie. I remember watching the cartoon as a kid and always giggling at the "10 times as big as a man" line in the theme. I don't know for sure if that makes it into the Japanese theme, but it sure is catchy!
Here's the pilot episode:
This version doesn't have the Japanese lyrics added but it does have an added bonus. Halfway through is a tv show I don't ever recall watching but I do remember hearing about it: 001/7親指トム (ゼロゼロななぶんのいちおやゆびトム = zero zero nana bun no ichi/aya-yubi Tom) = Tom of T.H.U.M.B.
Here's a full episode in English. I can see why I don't recall this. It's dreadful! What's with the WC Fields voice and the Asian sidekick? I do like his name though...Swinging Jack!
I'd always thought this was just another rank Rankin-Bass production and I just discovered that it was originally produced in Japan!. Way too much more information can be found here if you're truly interested. I do find it intriguing that this show was so popular in Japan that the characters got loaned out to Toho who proceeded to use them in the Godzilla vs King Kong series!