This straw circle is called a chinowa kuguri (茅の輪くぐり). It’s part of a purification ritual that you see at most major shrines during the New Year’s period. Stand in front of the circle, walk through it towards your left, return to the front, walk through it again towards your right. The white papers tied to the straw are called shide (紙垂), and are meant to prevent impurities from entering the sacred space. I took these photos at Ootori Jinja (鷲神社) in Asakusa.