It is said that, immediately after the surrender in World War II, several causes such as the deaths in the war of the successors of many schools resulted in their shitsuden (the interruption and loss of the tradition).
第二次世界大戦敗戦直後、沢山の流派において継承者が戦死するなどの原因から失伝（伝承が途絶え、失われること）したという。