You can learn about the structure of a blues song
on Wikipedia. I don't think you can learn about the structure of "Japanese popular music." The
J-pop article has a history section but no information about the structure. So thanks for explaining it.
The Kaminomi OPs don't have a chorus, it goes sort of like ABCD.
For iM@S songs, game versions are 125 seconds long. Often you will find one of the last parts of the game version is a repeat of the chorus. Anime OP versions of songs usually end with the B part.
I had no idea what PPPH was, so if you're like me go
here. I couldn't find it explained in English. I still don't know what it is. Pan Papan Hyuu?