Unmarked in the centre of the box, Tanaka beat exposed goalkeeper Kang Ju Hyok and put Japan a step closer to the 2026 World Cup.
North Korea's Ri Il Song (R) competes for the ball with Japan's Ao Tanaka during the FIFA World Cup 2026 and AFC Asian Cup 2027 preliminary joint qualification round 2 match between Japan and North Korea at the National Stadium, March 21, 2024, in Tokyo. Photo by AP |
They have three wins from three in their group and are firmly on course to reach the next stage of qualifying.
The victory was an unconvincing but welcome return to winning ways for Japan after a disappointing Asian Cup.
Soon after taking the lead Daizen Maeda shot wide as Japan threatened to run riot. Hidemasa Morita and Ritsu Doan also had chances for the hosts.
North Korea were much livelier in the second half.
They were cheered on by a contingent of supporters from Japan's 300,000-strong ethnic Korean community, waving flags and with their faces painted.
Han Kwang Song's left-footed shot hit the post before Jong Il Gwan slotted the ricochet into the net, but he was ruled offside.
Japan were playing for the first time since their quarter-final exit at the Asian Cup, where they lost 2-1 to Iran.
They are scheduled to play the return leg against North Korea on Tuesday in Pyongyang, Japan's first game there since 2011.
Japan are missing Brighton winger Kaoru Mitoma and Arsenal's Takehiro Tomiyasu, both injured.