TANABATA, also known as the "star festival," takes place on the seventh day of the seventh month of the year, when, according to a Chinese legend, the two stars Altair and Vega, which are usually separated from each other by the Milky Way, are able to meet.
Tanabata originated more than 2,000 years ago with an old Chinese tale called Kikkoden. Once there was a weaver princess named Orihime and a cow herder prince named Hikoboshi living in space. (True Sci-Fi Theater stuff!)
After they got together, they were playing all the time and forgot about their jobs. The king was angry at them and separated them on opposite sides of the Amanogawa River (Milky Way). The king allowed them to meet only once a year on July 7th. This is why Tanabata is also known as the star festival. It's believed that Orihime and Hikoboshi can't see each other if July 7th is rainy, so people pray for good weather and also make wishes for themselves. (Good news here: The weather is clear.)
Because the seventh month of the year roughly coincides with August rather than July according to the formerly used lunar calendar, Tanabata is still celebrated on August 7th in some regions of Japan, while it is celebrated on July 7th in other regions.
One popular Tanabata custom is to write one's wishes on a piece of paper, and hang that piece of paper on a specially erected bamboo tree, in the hope that the wishes become true.
I'm off to hang my wishes from the magnolia tree in the front yard - femminismo