During the latest years of the Tokugawa Shogunate (also called the bakumatsu period), there was a huge fight between the two major clans in Japan: Shinsengumi (the clan that supported the shogunate) and Choshu (the clan that supported the emperor).
They always had fights mostly in Kyoto where the emperor lived.
The guns were banned so the fights involved the blades and of course the katana.
In July 1864, the Choshu clan was planning to set fire in Kyoto to create a chaos and bring back the emperor to power.
But the Shinsengumi attacked them in a place called Ikeda Inn.
The fight continued on the nearby bridge and the blade traces can be seen today.
The shinsengumi were outnumbered but won the fight by killing 8 members of the Choshu clan and arresting dozens of the Choshu clan members.