The scorched-earth strategy was in preparation for a worst case scenario such as; the 'expeditionary force to the east' declining to accept a petition by the Tokugawa family, then proceeding with an attack; or, in the event of the 'expeditionary force to the east' only accepting those conditions which would have extended humiliation and other intolerable actions upon the retainers to the Tokugawa family.
もし東征軍側が徳川家の歎願を聞き入れずに攻撃に移った場合や、徳川家臣の我慢の限度を越えた屈辱的な内容の条件しか受け入れない場合の作である。