Nintendo's Wii game console outsold Sony's PlayStation 3 by more than five to one in Japan last month, Japanese video game magazine publisher Enterbrain said.
Nintendo sold 251,794 units of the Wii in May, compared with 45,321 units of the PS3 sold, it said.
Nintendo launched the Wii in November. The device features a motion-sensitive controller that allows users to direct on-screen play by swinging it like a tennis racket or wielding it like a sword, opening a new avenue of game playing.
Rival Sony also started selling the PS3 late last year, but has seen slow demand so far due to its high price tag and limited availability of attractive software titles.
Separately, Sony will spend about 60 billion yen (US$495 million) over the next three years to boost its capacity to make image sensor chips, the Japanese electronics and entertainment conglomerate said on Wednesday.
Image sensor chips are used in digital cameras and camcorders, Sony's cash cow products.
Sony did not say how much capacity will be added by the investment, but the Nikkei business daily said it is expected to boost output capacity at its microchip plant in Kumamoto, southwestern Japan, by 20% to more than 20,000 units of 300-mm silicon wafers a month.
Sony's semiconductor sales totaled 780 billion yen in the year ended March 31, accounting for 9.4% of its overall revenues.