Five temples in the Kyoto Prefecture had blood-stained ceilings.
The ceilings had been made of floorboards from the Fushimi Castle.
In 1592, 10 warriors had held off attackers of the castle for several days while a man of a higher status, Tokugawa, escaped.
Realizing they were about to be overtaken, the men surrendered with honor, killing themselves by opening their bellies with a sword.
The blood soaked into the floorboards, where they remain today.