Brazil took a staggering 26 shots, 10 of which were on goal, while Japan managed only two shots on net on a frigid night in Johannesburg.
Player of the Game
Elano made a beautiful pass to Maicon to get Brazil on the board early in the second half, and then tallied one of his own in the 72nd minute.
Maicon opened the scoring in the 55th minute on a pass from Elano, whoh found the back of the net 17 minutes later on a well-timed pass from Robinho.
Ji Yun-Nam put North Korea on the board in the 89th minute and brought the match to within a goal, but that was as close as the North Koreans would get.
Brazil dominated the time of possession by controlling the ball 73 percent of the time.
The temperature for the game was 34 degrees, with a wind chill of 24.
Brazil has won all of its opening World Cup matches since a 1-1 draw with Sweden in 1978.
Brazil takes on Ivory Coast on Sunday, June 20, at 2:30 p.m. ET. North Korea faces Portugal on Monday, June 21, at 7:30 a.m. ET.