Heavy rain has caused flooding and mudslides in southern Japan.
At least four people were injured during the severe weather, while dozens of homes have been damaged and hundreds left without power.
One missing person was possibly buried under the same mudslide where another had been confirmed dead, according to deputy chief cabinet secretary Yasutoshi Nishimura.
The casualties occurred in the hardest-hit southern prefecture of Kagoshima.
Prime Minister Shinzo Abe pledged to “do our best for rescue and life-saving activities”.
Nearly 80 houses were damaged in Kagoshima and the two other southern prefectures of Miyazaki and Kumamoto. About 1,700 houses were without power.
Videos on social media showed a river in Kagoshima swollen with muddy, brown water threatening to overrun its banks.
Kagoshima governor Satoshi Mitazono requested the help of military personnel in the rescue effort. About 14,000 troops were on standby.
He said rainfall since the weekend has exceeded one metre in areas.
He cautioned residents against landslide risks and urged them to stay up to date with weather reports.
More than one million residents had been advised to evacuate to shelters.