|Photo from Bite-JAPAN|
On this night, it is said that two deities meet in the Heavens. Altair and Vega, as they are known by Western names, which are called 'Orihime-boshi' and 'Kengyuu-boshi'.
Tanabata was brought over from China during the Heian era, but wasn't incredibly popular until almost 1,000 years later, in the Edo era (1603). Once, Obon and Tanabata were only a week apart, and still are in some regions, so celebrations would get mixed the entire week. There were once two other festivals that mixed and became a part of today's Tanabata. It's celebrated differently depending on where you live because (as with most Japanese festivals) local religions or beliefs mixed in with the adapted holiday. For the most part, it is a day for airing out wishes! Traditionally, women wished to sew and weave better, since most fabric was made by the families who wore it. Men wished for better academic skills, or for other useful skills. Wishes today are written on slips of paper and hung on special bamboo poles; before, they were attached to trees.
The story is a romantic one, and also one of heartbreak.
The Sky God Tentei had a beautiful daughter, Orihime, who was a skilled weaver and made some of the finest fabrics in all of Heaven. Daily, unendingly, she wove this beautiful fabric by the side of the Amanogawa (Amano River). But, as in love as she was with her work, she was very lonely and wished for a companion. Her father, seeing her distress, arranged for her to meet Kengyuu the cow herder. They were a good match- so good in fact, that as deeply as they fell in love with each other and forgot the rest of the world. Cows roamed all over the universe, and the shortage of cloth quickly became an issue in the Heavens. Problems mounted for everyone the longer they were together. Furious, Tentei separated them, but it didn't help- Orihime became so depressed, she couldn't work again. Only with the promise of being able to meet each other every year would either be able to go on. Now, every year, Orihime and Kengyuu are allowed to see each other during the seventh month before parting ways again.
Of course, there are other stories, but this is probably the most famous one.
Another version is that a goddess named Tanabata came to Earth for a visit, but she lost one of her kimono somehow. A farmer named Mikeran found it and took it. When she returned to ask about it, he lied to her and said he had never seen it. He was such a charming person however that she fell in love with him. But later, Tanabata saw the fabric from her kimono drying. When she approached him about it, he finally admitted to his deception. The Goddess, being merciful, made him swear to weave her 1,000 pairs of sandals and plant them under a bamboo tree. Some say he was able to, but only planted 999 of them, causing him to fall short, but was allowed to see her only once a year. Some say he couldn't do it in his lifetime, and as a consolation, could meet her yearly in Heaven. Every version of this story is a little different.
Today, probably one of the oldest and most famous Tanabata festivals is in Sendai, which goes all the way back to the Edo era. One in Hiratsuka is also very popular. Big processions of paper lanterns, trees of wishes, and paper representations of wishes such as gold coin pieces or symbols of a good fishing year are made and marched throughout town. Shinto priestesses who still know how to weave may make a small piece of fabric by a river while meditating in honor of Orihime. Women go around in fashionable yukata, and men tend to wear very casual clothes or yukata or happi coats. All in all, Tanabata is usually not only celebrated for one night, but for a few nights, so there is lots of fun to be had! Hopefully, it will not rain during the Festival this year. It is said that bad weather could cause Orihime and Kengyuu not to meet. However, really, all that paper out in the streets getting wet- eek! So, hopefully, the rain can hold on for a few days!
If you want to know more, perhaps one of the most complete, interesting articles I've read is from this site. I highly recommend exploring it! You can even find out where some festivals are held locally in Japan, so if you are visiting, you can plan for upcoming holidays during your vacation!