TOKYO — Record torrential rains across western and central Japan unleashed flooding and landslides in several residential areas, killing dozens and triggering weather warnings in four districts of the country.

By Saturday evening, at least 76 people were killed and scores of others were missing, according to the public broadcaster NHK. More than one million people in 18 districts had been ordered to evacuate their homes and 3.5 million others had been urged to leave.