I also bought a copy of "Oyoge! Taiyaki-kun", which is the biggest-selling 7" single of all time, in Japan. Possibly still the biggest-selling single, depending on which reports you read. (Some stories report that Utada Hikaru has overtaken this in sales thanks to downloadable singles being counted in the charts).
Being the biggest-selling record ever, 4.5 million copies sold, there are tons of copies around (even for a record from 1976!) so mine only cost $1.99 ^_^ I already had a copy of the song on a compilation CD, but it's symbolically nice to own a copy of such an important record.
It's a bit like the story of the gingerbread man, it's a short children's song animation. You can watch it here
Every day the baker makes taiyaki and it gets eaten. One day, the taiyaki gets bored of this, gets into a fight with the baker and decides to escape, and it goes off and swims in the ocean. It has a nice time there, lots of fun swimming about, but eventually it gets hungry. So it looks for some food, and sees a worm hanging about in the water.... some old guy fishes him out! What a surprise! So he gets eaten.
There's a live version here too:
http://www.megavideo.com/?v=XPHOOBLL
Hooray for Masato Shimon! Isn't he great? Why is he surrounded by businessmen, clapping? Well, it seems that the reason this was such a big hit was not just because it's a great song, but everyone in Japan could relate to it as a metaphor for working life.
...isn't that somewhat depressing? I guess it depends on your interpretation.
Apparently due to contracts, Masato Shimon didn't make much money out of this at all. :( The record company made enough profit to build a new building just from this one record, though.