In Japanese mythology the seventh day of the seventh month is the festival of Tanabata (meaning the “night of the seventh”) on which day Orihime and Hikoboshi, two lovers separated by the milky way, are allowed to meet once a year.
Winters are relatively dry in Japan. As it happens, the Milky Way also appears thinner and less dense in winters. July is the rainy season (called Tsuyu) and the Milky Way looks much denser in the sky – like a swollen river.
The old Japanese, when they looked up at the night sky in July, they saw two bright stars coming closer to each other on the banks of a river of light: Vega which they believed was Orihime, and Altair which had to be Hikoboshi.
Among many traditions, they write wishes on pieces of colorful paper (called tanzaku), and hang them on branches of bamboo. The bamboo and paper wishes are typically set afloat on a river (perhaps symbolizing the journey on the Milky Way) after the festival.
Below is a traditional Tanabata song:
Sasa no ha sara-sara
Nokiba ni yureru
Goshiki no tanzaku
watashi ga kaita …
sora kara miteiru
Bamboo leaves rustle,
swaying in the eaves.
Majestic stars glitter
on the gold and silver grains of sand.
On the five-color paper
I have written …
Glittering majestic stars,
are watching us from heaven.