For the first time since 2004, China has failed to win gold at an Olympics table tennis event.
Japan's mixed double duo came back after losing two sets to win Monday's final.
Since 1996, the only table tennis event not won by a Chinese player or pair was the men's singles in 2004.
Of the 32 gold medals given out in the sport since 1988, China has won 28.
South Korea and Sweden had been the only two other countries to have won a gold in the sport until Japan's shock victory.