Itadaki Street Special

my friend has a copy of Itadaki Street SPECIAL MOBILE for the PSP. I want so bad, but I do not buy it if there is a region code on this. I thought all PSP games could play on any PSP, as it is not a region code for the Games. Am I wrong?

you can play all games on PSP in Japan, but American movies you can not. Thus, on a U.S. PSP you can only play Region 1 UMD.

All games have region codes, but the real handhelds (like the PSP) does not read them. For example, a handheld in North America would be able to play games in Asia without any problems.