The two powerful earthquakes hit the south-western island of Kyushu.
Saturday’s magnitude-7.3 quake struck at 01:25 (15:25 GMT on Friday) close to the city of Kumamoto, which had been hit by a magnitude-6.4 quake on Thursday night.
At least 100,000 people are still thought to be living in emergency accommodation, some living in their cars enduring cold temperatures. Relief efforts are continuing in southern Japan amid hundreds of aftershocks after two deadly quakes.
The US military has joined tens of thousands of Japanese troops and emergency services personnel in the relief effort.
