During the Warring States period in Sagami (相模), the most common word used for shinobi was "Rappa (乱破)". The most famous Rappa were the "Fuma-clan (風魔一族)", and their most famous leader was Fuma Kotaro (風魔小太郎). The stronghold of the Fuma-clan was "Hakone (箱根)", which is a mountainous area that is now famous for hot springs and sightseeing. They were under the protection of the "Hojo-Family (北条氏)". According to Hojo Godaiki, the journal of the five generations of the Hojo Clans, they were a band of 200 people specializing in horseback guerrilla warfare, night raids and infiltration, as well as being proficient at deception. They were divided into four subgroups of pirates, mountain brigands, burglars and robbers. They were closer to being mercenaries than ninja. The clan was based in Kanagawa.
When the Fuma-clan fought a fierce battle against the Koshu-clan known as the “Koshu-Toppa”, the Koshu clan planted spies in the Fuma-clan. Just after the Fuma-clan broke out from Kousyu, their boss Fuma Kotaro gathered all his members on a river and Kotaro made them sit down right there. Kotaro shouted Fuma's secret question while swinging a torch so abruptly everyone stood up. The Koshu clansman who did not know the answer were slayed right away. This was both a simple and effective way to distinguish their enemies and real members immediately.