The mother of all Tanabata Matsuri festivals in Japan. You haven’t seen a Tanabata festival until you see the one in Sendai held annually on Aug. 6th–8th. The colors, variety, creativity, and intricate designs are breathtaking. Other Tanabata festivals have mostly factory-made plastic decorations, but not in Sendai. Most are handmade and one-of-a-kind. Changes every year too.
Commonly called the Star Festival, Tanabata Matsuri features large, colorful, hanging streamers called take-kazari (竹飾り) festooning large shopping arcades near JR Sendai Station (west side). One take-kazari decoration can cost hundreds of thousands of yen or even a few million yen. (Thousands or tens of thousands of US dollars.) It’s one of the Big Tohoku Summer Festivals. Although it was canceled in 2020 due to the pandemic, it will be held in 2021 with a few modifications and safety rules.
The festival is said to have originated from a Star Festival in China. According to Chinese legend, east of the Milky Way was the King of the Heavens whose daughter worked as a weaver. However, when she married a herdsman, she quit weaving. This angered her father who banished the herdsman to the other side of the Milky Way. He allowed the two to meet only once a year on the evening of the seventh day of the seventh month (according to the lunar calendar). The weaver is represented by the Vega star and the herdsman by the Altair star. As a prayer to produce better arts and crafts, the Japanese Imperial Court and warrior class paid homage to these two stars since ancient times. This practice spread to the masses.
The modern Sendai Tanabata Matsuri started in 1928 during the Tohoku Industrial Expo. Local merchants started the festival and their goal to attract shoppers and visitors has succeeded spectacularly. Tanabata is therefore not a religious event and not held by any Shinto shrine or Buddhist temple.
Today, it sees 2 million visitors (pre-Covid). You’ll notice that many of the Tanabata decorations are quite commercial, with sponsors or advertisers prominently displayed on the streamers. Tanabata has spread to other cities in Japan like Hiratsuka in Kanagawa and Asagaya in Tokyo.
In Sendai, the Tanabata decorations are judged, and awards are given to the winners. At the end of each day during the festival, the decorations are put away or hoisted well above the reach of passersby. So each morning, before stores open, store employees unpack and prepare their Tanabata decorations for the day. The right middle photo shows shop employees using a straw to reinflate paper balloons shaped like an owl. The right bottom photo shows people spreading out the origami crane wings on their decoration.
When you walk through the Tanabata shopping arcades, you hear lots of oohs and ahhs. The creativity and laborious work that go into the decorations are amazing. Many of the decorations are low enough to touch, but from this year, I’m expecting a “no touching” policy due to Covid. I’m expecting the decorations to be hung higher or be shorter than usual. And no eating while walking.
Another Tanabata tradition is to write a wish on a vertical piece of color paper and hang it on a bamboo branch. Everyone of course will wish for the pandemic to end soonest. After the festival ends, most of the decorations are discarded due to the lack of storage space. Tohoku is a great place to be in early August. 
More photos of Sendai Tanabata Matsuri: https://photoguide.jp/pix/thumbnails.php?album=332
Official: https://www.sendaitanabata.com/en
Closest station is JR Sendai Station on the Tohoku shinkansen.