Thus TAKAHASHI recommended INO to the Bakufu and asked for permission to measure a degree of the meridian by surveying North Kanto and Tohoku regions on his way to and from Ezochi (inhabited area of Ainu, the present Hokkaido) which he would survey as well because coastal defense had to be strengthened there in case of an advance southward of the Russian Empire.
そこで高橋は幕府に伊能を推薦し、当時ロシア帝国南下の脅威に備えて海岸線防備を増強する必要があった蝦夷地（現在の北海道）の測量を兼ねて、その往復の北関東・東北地方を測量することで子午線1度の測定を行わせるよう願い出た。