Setsubun is a Japanese tradition that celebrates the coming of spring, and it takes place in the beginning of February. One of the main customs during Setsubun involves a bean-throwing ceremony called mamemaki, where people throw roasted soybeans both inside and outside their homes to chase away evil spirits and bring in good luck.
A special event hosted by Chichibu Railway takes that bean-throwing fun onto their train network, starting from Kumagaya Station. The train will stop at Yorii Station, Nagatoro Station, and Chichibu Station (the final stop), and passengers will be able to throw beans at the "demons" that appear on the train platforms.
Advance reservations for the Setsubun train event aren't required – just be at Kumagaya Station from 10:50 to 11:20 where staff will let you know what to do. The fee is just the standard train fare.