Because Okubo, Saigo and Takayoshi KIDO already proceeded with the preparations for the returning of lands and people to the emperor focused on haihan-chiken (abolition of feudal domains and establishment of prefectures) in the future but if returning of lands and people to the emperor realized, this means denying fundamentally the master-servant relationship of the load of domain and the feudal retainer of domain which continued for more than 250 years as an absolute principle, so a single misstep could be a cause of a nationwide rebellion.
なぜなら、大久保や西郷、木戸孝允らは既に将来的な廃藩置県を見据えた版籍奉還の準備を進めていたが、版籍奉還を行えば幕藩体制において絶対的な原理として250年以上続いてきた藩主と藩士の主従関係が根本的に否定することになるため、一歩間違えれば全国的な反乱を引き起こしかねないものであった。