Piano Books of JPOP in Tokyo

Hi everyone!

I will be going to Japan in a few weeks time. I am a piano player and would like to buy some piano books with JPOP songs this time in Tokyo. Does anybody know where there is a huge collection of such books?

Perhaps a high-reputation bookstore in Tokyo?????
Keep in mind that I am looking for JPOP piano pieces, nothing to do with anime songs.

Do they have JPOP piano books in HMV....doubt it though.

Thank you for all your help!

^_^

I bought my J-pop Piano Books and scores in the music dept of Pepe Department store near East exit of Shinjuku Station. They also do guitar picks with various j-rockers names on them. I frequently buy L`Arc~en~Ciel`s guitar picks for my friends. (^_~)v
If you need help finding the store, then let me know when you get here and I can meet you at the station and show you.