Tanabata festivals are traditionally held throughout Japan on July 7, a date based on the old Chinese calendar. The Sendai Tanabata Festival, however is held annually from August 6 to 8, based on a calendar that is one month later than the old Chinese calendar, in order to keep to the seasonality of the old festival.
During the festival, the entire city—including central Sendai and neighboring shopping districts—is filled with colorful Tanabata decorations. The festival is visited by more than two million tourists every year.
Due to crowds for the festival, be prepared to park away from the actual festival site.
Click on the website link for a helpful guide and map.