Therefore, in 1884, the members of the prefectural assembly of Ibaraki Prefecture who were dissatisfied with the measures for flood control of the Chiba Prefecture side and those elected in the Boso Peninsula of Chiba Prefecture cooperated to launch the campaign for changing the prefectural border in which, in exchange for offering the region of Chiba Prefecture on the northern side of the Tone-gawa River to Ibaraki Prefecture, Ibaraki Prefecture should pay some of the expenses of the construction for flood control of the Tone-gawa River.
そこで明治17年（1884年）、千葉県側の治水対策に不満を抱く茨城県と房総半島選出の県議達が連携して利根川以北の千葉県域を茨城県に譲る替わりに利根川の治水工事に茨城県が費用を負担するとした県境変更運動を開始したのである。