May 5 is Children's Day in Japan, they observe Tango-No-Sekku (Boy's Festival) to celebrate children's healthy growth and happiness. From late April to early May families display brightly colored carp streamers hoisted on a bamboo pole outside their homes called Koi-Nobori, a carp is flown for each son in the family - with the sizes ranging from big (eldest) to small (youngest). Why the carp? the Japanese consider it the most spirited of fish, because of its strength, vigor, and perseverance when swimming upstream.
Inside the house, families display armor, swords, bows, and Boy's Day Dolls (gogatuningyo). The kuma0rila blog has now put up this new Relax Bear papercraft with Relax Bear (Rilakkuma) himself on a carp suit and his friend Korilakkuma wearing a cute red apron of some sort.