Sony has moved out of Japan and is now raping fathers and mothers in the US and others. Only explanation I can think of.

Can we blame Wii Fit?

There's a lot of possible reasons. One suggestion is that Japanese gamers are replacing their PSP original models with PSP Slim models en masse. Another is that pirating of PSP games has taken off in Japan. Still another is that the failure rate of early PSP models is catching up with them, and users are replacing their systems for that reason. It could even be something else entirely from any of those, for all we know.

FF7:CC?

Japanese hardcore gamers are upgrading from DS to psp.

Now thats the best explanation I can think of.

the new Mint Green PSP?

They found out PSP already had Valkyrie profile and were like, holy crap! I was excited for it on the DS, but it's already out on PSP!!!! My decisions been made!

@soriku

Then I dont understand why? The psp cost more than the DS,and according to you, its games are not meant for the japanese.

Maybe its that DS sales are dropping psp sales are holding steady.

Because the PSP was stronger early in its life cycle in the west and weak in Japan, now the DS has COMPLETELY saturated Japanese soil it is still selling strong, but nothing incredible. The PSP started out hot and was actually the favorite to win in the west... now the DS has caught on and NA is less than 50% of what it will be(total DSes sold) the same thing can be said for Europe. PSP has seen its best days in the west. DS has seen its best days in the east.

Japan gets all the freaking colors. Contrary to popular (or at least Sony's) belief, some Americans do like variety. Black, white, and silver are cool, but some of us like more variety. Yeah, there are others, but Japan definitely has the most. =P I kinda like that ice blue PSP or whatever its called.