Tango-no-Sekku

Tango-no-Sekku (Boys' Day Festival)

May 5The Boys' Day Festival in Japan dates back to the Tokugawa period (1603-1867). For centuries, Japanese farmers had frightened off harmful insects by hanging brightly colored banners and scary figurines in their fields. These later came to resemble warriors and rather than being placed in the fields, they were kept in the house to encourage young boys to imitate samurai warriors' courage—a practice approved by that era's rulers. In the latter part of the 18th century, people decided that the indoor display wasn't enough, and they started flying tubular wind-socks in the form of carp from poles outside their houses. To commemorate the old days, however, families set up tiers of shelves bearing figures of warriors and their equipment—armor, helmets, swords, etc. These miniature figures were treasured and kept for the festival from one year to the next.
The celebration, since 1945, of Kodomo-no-Hi, or Children's Day, was intended to replace Tango-no-Sekku. But in fact, many of the activities associated with May 5—which include sumo wrestling, kendo (fencing with bamboo staves), and climbing competitions—tend to focus on boys.
SOURCES:
JapanFest-1965, p. 69