Famitsu, through its parent company Entertbrain, has revealed first week data for the PlayStation Vita in Japan. The site reports that Sony’s new handheld sold 321,000 units thus far.

In actuality, Vita’s first week accounts for just two days of sales. The system launched in Japan on Saturday, and had one extra day of sales.

To compare, the 3DS moved 371,326 units in its first two days on the market. The PSP sold 166,074 units in its first week back in 2004, though that number is based on only one day of sales.

First week sales comparison

DS – 441,485
Wii – 371,936
3DS – 371,326
PlayStation Vita – 321,407
PSP – 166,074
PlayStation 3 – 88,443
Xbox 360 – 62,135
PS2 – 630,552
GBA – 611,504
GameCube – 133,719
Xbox – 123,929
Dreamcast – 101,490

Source