At first, the data showed below may be surprising for you. But it is not unexpected result for gamers in Japan.
#As a general trend, first day of Nintendo isn't so high and drastically inclreses in Sat. and Sun. This is because the main parton base of Nintendo games is family. The people buy games at release day are mainly gamers. Many people like children and family buy games weekend.
Fate/stay night Realta Nua (PS2) : about 90k
Persona 3 Fes (PS2) : about 65k
Super Paper Mario (Wii) : about 70k
Final Fnatasy (PSP) : about 30k
Nodame cantabile (DS) : about 1.5k
Clubhouse Games (with wi-fi) (DS) : about 7.5k
The Atelier of Lise (DS) : less than Clubhouse Games.
source : http://ameblo.jp/sinobi
If you need something about Japanese market from the perspective of Japanese, please contact me.