The Feast of the Weaver (Tanabata Matsuri) falls on 7th July and is one of the oldest festivals in Japan, based on a legend which originated in China.
The legend is about a princess who wove clouds, fog and mist for her father, the king of the sky. One day the princess was wading in the stream called the Milky Way where she met and fell in love with a handsome ox herder. They were so happy together that the princess forgot about going home to her father. The king of the sky became very worried and angry and came to take her home. To prevent the princess from seeing the cowherd ever again, the king poured star water into the milky way until the shallow stream became a mighty river which the cowherd and the princess could no longer cross to see each other. The princess missed the cowherd so much that she could not weave and over time the sky became emptier and emptier of clouds, fog and mist. On seeing this, the king told his daughter that if she worked hard he would let her go and see the cowherd once a year on the seventh night of the seventh month. On that night each year they were reunited by a bridge made of magpies, provided the weather was fair. If it was rainy they would have to wait until the next year.
This is why, on the 7th of July, Japanese children decorate bamboo branches with bright pieces of coloured poetry paper with their wishes on them, to remind the king of the sky that it is time for him to keep his promise again. Coloured threads are also hung on the bamboo branches. The custom of decorating a bamboo arose from the belief that if you wrote poems or proverbs on strips of paper and offered them to the stars, you would acquire good penmanship skills.
The popular custom of praying to the cowherd for a good harvest and to the weaver for skill in weaving has been observed in Japan for centuries in connection with this festival.
The Tanabata Festivals held in Sendai (Miyagi Prefecture) and Hiratsuka (Kanagawa Prefecture) are two of the most famous festivals in Japan.