When an Ochuro, a subordinate of an Otoshiyori, was selected for yotogi, became pregnant, and the son became the heir to the shogun and was proclaimed Shogun later, the Otoshiyori could become quite powerful in O-oku.
自らの部下たる御中臈が夜伽の相手に選ばれ懐妊し、更にはその子が将軍世嗣となり、後々その世嗣が将軍宣下を受けた場合、その御年寄は大奥内で大きな力を持つことが出来た。