According to the ninjutsu records of Kōga Ryū, during the Tenkyō era (天慶 938-46), Mochizuki Saburō Oki-no-kami Kaneie (望月三郎隱岐守兼家), the third son of Suwa Saemon Minamoto Shigeyori (諏訪左衛門源重頼) and a resident of Suwa in Shinano Province (諏訪郡信濃国), he joined Taira Sadamori (平貞盛) and Fujiwara Hidesato (藤原秀郷) against the rebellion of Taira Masakado (平将門) and for merits in battle he was promoted to governor of Kōga (甲賀郡), southeast of Ōmi Province (近江国). He changed his name from Mochizuki Saburō Kaneie to Kōga Saburō Ōmi-no-kami Kaneie (甲賀三郎近江守兼家). His son, Ōmi-no kami-Iechika (近江守家近) with literary and military achievements (文武両道), is said to have been tutored by a monk named Tatsumaki Hōshi (竜巻法師), a genjutsu master (幻術) from the area of Ryūbōshi (竜法師) in Kōga from which it may have gotten its name. According to legend, this could be the origin of Kōga Ryū ninjutsu (甲賀流忍術).

Mochizuki Saburō Kaneie of Shinshū (信州主人望月三郎兼舎) according to the Toki Ōmi Kōga-no-Katsudoki (時近江甲賀勝時)

From then on the Mochizuki clan would be divided into two main branches, the original Shinano Mochzuki (信濃望月氏) and the Kōga Mochizuki (甲賀望月氏). The Shinano Mochizuki family, famous for horse breeding, was part of Minamoto Yoshinaka's army and one of Yoshinaka's four trusted generals, Neoi Yukichika (根井行親), is said to have descended from the Mochizuki clan. Later in the Sengoku period (戦国時代), within the original branch we find Mochizuki Moritoki (望月盛時), a warrior who served the Takeda clan (武田氏) and is said to have been married to Mochizuki Chiyojo (望月千代女) a Kunoichi (くノ一) in the service of Takeda Shingen (武田信玄) who instructed other women with the mission of gathering information due to her status as Arukimiko (歩巫女), a wandering priestess.

Later descendants of Kōga Saburō, from the Kōga Mochizuki branch, were known as Tenryū Kōga (天龍甲賀), Chiryū Kōga (地龍甲賀) and Aranami Kōga (荒波甲賀) and families such as Mochizuki, Yamanaka (山中), Akutagawa (芥川) , Ueno Ban (上野番) and Nagano (長野) among others, formed the 21 and 53 families of Kōga (甲賀五十三家), collaborating closely with the Sasaki Rokaku clan (佐々木六角氏) and forming an independent structure as the different families from their neighboring area of ​​Iga (伊賀郡).

Record of the 21 families according to the Kōga Nijūichi Ke Senzo Sho (甲賀二十一家先祖書)

Although the legend of Kōga Saburō would mark the beginning of the Kōga shinobi in the Heian period (平安時代), according to documents such as the Shinobi-no-jutsu Ōgi Den (忍術應義伝), attributed to Mochizuki Shigeie (望月重家), they explain that Ootomo Hosobito (大伴細人), from the Kōga area, served Shōtoku Taishi (聖徳太子) and was given the first name Shinobi (志能便) which recognized him as a "specialist in obtaining information". This legend would place the first shinobi of Kōga in the Asuka period (飛鳥時代), about 300 years before that of Kōga Saburō Kaneie.

Tres extractos del Ninjutsu Ōgi Den (忍術應義伝) atribuido a Mochizuki Shigeie (望月重家) descendiente de Mochizuki Kōga Saburō (望月甲賀三郎)

May 5th, 2024, Ensanryū 鳶山龍

Bibliography:

戦国忍法図鑑, author 初見良昭, year 1978

Essence of Ninjutsu, author Hatsumi Masaaki, year 1988

Takeda Shinobi Hiden, author Serge Mol, year 2016