(甲賀流, “School of Kōga”; occasionally transliterated as “Kōka”) is an ancient school of ninjutsu, according to Japanese legend. It originated from the region of Kōga (modern Kōka City in Shiga Prefecture). Members of the Koga school of shinobi (ninja) are trained in disguise, escape, concealment, explosives, medicines and poison; moreover, they are experts in techniques of unarmed combat (Taijutsu) and in the use of various weapons.
The beginnings of the Kōga-ryū may be traced to near the end of the Muromachi period. While the town of Kōka was under the jurisdiction of the Rokkaku (lit. “hexagon”) clan, it was a kind of autonomous municipality composed of peasant unions, then called sō (惣). All important decisions in the municipality were made by a majority vote from the union representatives, this kind of system was uncommon for the period in question.
Sasaki Rokkaku of Ōmi Province, using Kannonji Castle as a base, started to steadily build up military might. He made light of commands from the Ashikaga shogunate, and eventually began to ignore the shogunate altogether. In 1487, General Ashikaga Yoshihisa brought with him an army to stamp out this rebellion, and a battle between Ashikaga and Rokkaku’s camps ensued. Ashikaga mobilized daimyo from several provinces against the castle of Kannonji, the headquarters of the Rokkaku; as a result, Rokkaku Masayori and Rokkaku Takayori (Masayori’s son) were forced to flee to the castle of Kōka. The factual accuracy of their escape is debated and it is likely that they gave up the town to avoid a direct confrontation instead.
Ashikaga then moved his base to Anshiyoji of Kurita District and attacked the castle of Kōka. Kōka fell, but the Rokkaku duo escaped again and ordered the Kōka warriors who followed them to mount a heavy resistance against Ashikaga using guerrilla warfare. Exploiting their geographical advantage in the mountains, the Kōka warriors launched a wide range of surprise attacks against Ashikaga’s forces, and tormented them by using fire and smoke on Ashikaga’s camp during the night. The guerrilla warfare prevented a final showdown, until Ashikaga died in battle in 1489, ending the three-year conflict and sparing the lives of the Rokkaku duo.
The elusive and effective guerrilla warfare used by the Kōka warriors became well known throughout the whole country. This also marked the first time that the ninja of Kōka were drafted as a regular army by their lord. Previously, they were only mercenaries and it was not uncommon to have warriors from Kōka on both sides of a battle. As a result of this victory, the local samurai in the 53 families who participated in this battle were called “the 53 families of Kōka”.
The last Soke of Kōga-ryū was 14th headmaster Fujita Seiko (1898-1966). In his own autobiography ど ろ ん ろ ん 最 後 の 忍 者 « Doronron : Saigo no Ninja » « The last ninja » October 1958 , Fujita Seiko categorically states that he has not and will not teach anyone Ninjutsu and would not pass on the school.
The Bugei ryuha dai jiten, a definitive Encyclopedia of Martial art schools, catalog of Koryū Bujutsu (old schools) and Gendai Budō (new schools) of Japanese martial arts (budo) States that no one knows this school today.
Few today, who state a connection to Koga Ryu, can show any evidence to back up this claim.
It is possible that another master passed the schoold down, some very elderly Japanese martial Artist claim that the footage of Daimyo Shi during one of his attacks certianly may have elements of the old Koga style. In the International Criminal Fighting area, a new Koga Clan does seem to exist with Daimyo Shi at least being a sinor member in this new clan. several members hae seemingly fought on both sides of the law however.