Kameido Katori Jinja (亀戸香取神社), located 10 minutes away from JR Sobu Line Kameido Station and pretty close to Kameido Tenjin Shrine, is a Shinto shrine founded in 665.
At this shrine, a parade event called the Kachiya-sai is held on May 5th annually.
Kachiya-sai at Kameido Katori Shrine
At the Kachiya-sai (勝矢祭), a procession event held at Kameido Katori Jinja on May 5th every year, is based on an episode that when legendary samurai Taira no Masakado who lived in the Kanto region rebelled against the Imperial Court in Kyoto in 939 and briefly (for two months) established his kingdom in the region including modern-day Tokyo, Fujiwara no Hidesato, who is another legendary samurai of this region, killed him as a general of the Kyoto side. On his way to the war with Masakado, Hidesato wished for his victory at this shrine, so after defeating Masakado, Hidesato, thanking the shrine divinity, offered to the shrine a bow and arrow, naming it kachiya -victory arrow-. Based on this story (which is probably only a legend,) parade participants clad in samurai armors march about 2 kilometers (1.2 miles) to Kameido Katori Shrine from south and offer arrows to the shrine.
The starting point of the procession is Kameide Shrine, a small Shinto shrine located a little east of Toei Shinjuku Line Nishi-ojima Station. The procession starts at 1pm.
The marching band of kids precedes the procession.
Students of a local high school in modern martial arts uniform.
The procession is scheduled to reach Kameido Katori Shrine at around 3pm. After crying of triumph "Ei, Ei, Oh!", they get into the shrine building to paractice a ritual.