"We are praying for the birth of a mascot that will be loved and praised by the world," Ryohei Miyata, a member of the organising committee, said at a news conference.
Japanese residents can submit their designs on the Tokyo 2020 official website during a two-week period starting on August 1.
A selection panel will draw up a shortlist for the schoolchildren to vote on. The prizes include tickets to some Olympic events and up to 1 million yen ($8,975) in cash.
The mascot has been a Games tradition dating back to the 1968 Winter Games in Grenoble, France.
More recently, Vinicius, an amalgamation of Brazilian fauna, was the mascot for the 2016 Olympics in Rio. Quatchi the sasquatch represented the 2010 Vancouver Winter Games, and Olly the kookaburra was created for the 2000 Sydney Summer Olympics.
(Reporting by Teppei Kasai, Editing by Karishma Singh)
