Translation of Ikeda Ryutaro's book "Koga-ryu ninjutsu" - is the first book in Russian to acquaint the reader with the true ninjutsu described in ancient treatises. The book contains a description of the history of ninjutsu and its main methods, authentic sources of the 16th-18th centuries are abundantly cited. The book is addressed both to practitioners of traditional military arts and to anyone interested in the history and culture of Japan.