If what's happening to Sony's Playstation Vita in Japan is any indication as to how it might fare once it's released in the U.S., Sony might want to consider a backup plan.

Playstation Vita (Sony)
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Despite strong first week sales of about 325,000, the new portable is dropping off quickly. Only 72,500 units were sold in its second week, followed by third week sales of just 42,600, according to sales tracking group MediaCreate.

That dropped the Vita to a dismal fourth place finish for the week ending January 1, trailing the Nintendo 3DS, Sony Playstation 3, and perhaps most damning, the seven year-old original PSP, which moved 63,000 units over the same period.

The tech-heavy handheld system is set to launch in the U.S. on February 22 for $249 (a $299 3G model will also be available), the same launch price as Nintendo's once-troubled 3DS. That handheld is now ruling the Japanese charts and performed well in the U.S. in December on the strength of several high-profile software releases. A 3DS price cut in September is also widely credited with spurring sales, though Sony has yet to announce any similar cuts prior to the Vita's stateside launch.

No Vita games were included in the week's Top 20 software chart, either, although Sony chalks that up to the system's reliance on digitally downloadable games, which don't register as retail releases.

Last year wasn't great for the Japanese game industry in general, which experienced an 8% drop in revenue largely due to declining software sales.
Here's the full Japanese hardware sales rundown for the week ending January 1, with the prior week listed in parentheses:

1. 3DS: 197,952 (482,200)
2. PS3: 67,199 (75,943)
3. PSP: 62,746 (101,121)
4. PS Vita: 42,648 (72,479)
5. Wii: 33,208 (91,176)
6. DSi XL: 3,356 (8,470)
7. Xbox 360: 2,453 (4,245)
8. DSi: 2,418 (5,894)
9. PS2: 1,659 (1,582)
10. DS Lite: 28 (32)