The Nintendo DSi is proving to be extremely popular.

The newest iteration in the company’s DS line of handheld systems, the DSi was announced at Nintendo’s media conference in October, less than a month before the Japanese release November 1.

Japanese gamers snatched up 170,779 units within the first two days after launch, which is more than 85 percent of the total first day shipments of 200,000 units, according to Japanese publisher Enterbrain.

But the DSi may not have enough going for it to keep up the initial success.

“The DS has reached a kind of plateau,” says Michael Cai, Director of Digital Media and Gaming for Parks Associates, “and I don’t think the DSi will appeal to all the DS owners to upgrade or help [Nintendo] further expand the market for the DS.”  

For the past half year, Sony’s PSP has consistently outsold the DS and DS Lite in Japan; Nintendo had hoped to rejuvenate lagging DS sales with the newer version.

The $190 (18,900 yen) DSi features 2 cameras, music playback, an SD card slot, and a DSi Shop for downloadable games. It removes the Game Boy Advance slot in favor of a slimmer build and slightly larger screens.

Nintendo shares jumped $0.80, or 1.87 percent, to $43.50.