Koryu jujutsu went further into decline firstly because the practice was halted owing to World War Ⅱ and Japan's defeat in the war, and secondly because many jujutsu successors were killed in the war.
古流柔術が更に衰退した原因として、その後の第二次大戦と敗戦の影響により稽古が行われなくなったり、また多くの継承者が戦争で亡くなったことがあげられる。