There is a tradition in Japan of holding moon-viewing parties to celebrate the harvest on the 15th day of the eighth month of the lunar calendar, believed to be the best time of the year to watch the full moon, and this year it fell on Sept. 13.
In some parts of Aichi Prefecture, including eastern Nagoya and the city of Nisshin, children walk around the neighborhood that night, calling on houses for treats — a local custom known as o-tsukimi dorobō (moon-viewing thieves). Variants of the tradition are also practiced in other parts of the country.
The custom, which resembles trick or treat, is said to be derived from the tradition of allowing children to snatch offerings, including rice dumplings and taros, during o-tsukimi.