Koka ninja first appeared in the first year of the Choukyou era (1487.7.20-1489.8.21).
To suppress the rebel Sasaki Rokkaku Takayori, Shogune Ashikaga Yoshihisa launched an invasion with his large army; The Koka warriors supported the Sasaki Rokkaku clan and made a lot of surprise attacks in the mountains.
At night Koka warriors secretly approached enemy headquarters, made a fire there and saved the Sasaki Rokkaku clan.
Mochizuki Izumonokami was impressed by the Koka warriors’ tactics and special abilities.
Since that time, people started to call them Koka ninja.
In the Sengoku period (Warring States period of Japanese history, approx. 1467-1568 CE) each Daimyo was supported by the shadows (ninja).
It was built in the Genroku era of the Edo period (1688.9.30-1704.3.13).
In the beginning of the Edo period, society became stable and even the memory of the Sengoku period (lasted 100 years) began to fade.
Toyotomi Hideyoshi changed the class system.
Mochizuki Izumonokami was impressed by the talents of the Koka ninja.
He wanted to protect his house and body from unexpected attacks so he created a lot of booby traps in his residence.
During the Nara period a lot of gigantic trees from Koka were used in the architecture in Nara and Kyoto.
Because of that, architecture, logical thinking and deep perception were cultivated in the Koka region.
The ninja invented tools and tricks, not for attack, but for quick escape from dangerous situations. This ninja house was really impressive in term of defensive construction.
On Kuyoumon (the Family emblem of Mochizuki’s family) a central star is surrounded by 8 stars. Kuyoumon has the meaning of “full moon”.
In the early Heian period, in the year 865, the ceremony of Komabiki (a ceremony in which the Emperor reviewed the royal family’s horses) that had previously been held on August 29th was changed to August 15th because that day was full moon.
On August 15th,the Shigeno Family presented many horses to the Imperial Court, and all those horses were give the name of Mochizuki (full moon) horses. The Shigeno Family had 16 pastures in Shinano, and all of all their horses were named Mochizuki.
After that, the Shigeno Family, which consisted of 3 Families: the Mochizuki Family, the Umino Family, and the Nezu Family, were called Three Shigeno Families.
From that time on, the emblem of the Mochizuki Family was the Kuyoumon – a circle with the eight luminaries.
The Nezu family’s emblem was the Tsuki ni maru – a circle with a moon inside. The Umino family’s emblem was Mutsurensen (Rokumonsen) Mochizuki Saburo was praised for his achievements during Taira-no-Masakado Rebellion in the Heian period, and became the Founder of the Koka Mochizuki Family and began to use Kuyoumon as his family’s emblem.