Nintendo may have a new enemy: dating simulators.

Sales for the 3DS took a nosedive in Japan last week as Sony's PSP overtook the top spot. The reason: Amagami, a three-year-old dating simulator released originally for the PS2. More than 69,000 copies if Amagami were sold between March 28, and April 3, giving the title the number two on the charts.

During that same span, Nintendo sold 42,979 units, 8,000 less than the week prior. Sony, on the other hand saw PSP sales spike by 7,000 units to 58,075.

That's significant for Nintendo, which launched its latest handheld Feb. 26. Sony's PSP, on the other hand, was released in 2004, with its most recent iteration, the PSP Go, appearing in 2009.

So far sales for the 3DS have fallen well below company expectations. Japanese sales tracker Media Create reports that Nintendo has only sold 836,000 units of the 3DS in Japan, leaving a significant percentage of the device's initial 1.5 million shipment unsold.

Demand for the company's latest handheld has been weak due mostly to the devices thin launch line up. While nine titles were launched with console, many gamers have been left without a compelling reason to invest in the 3DS. 

Nintendo's share prices have dropped 17 percent since February. Like many Japanese companies, Nintendo has also been affected by the trio of disasters that struck Northern Japan last month.