一都三県

Tōkyō Chiba Saitama Kanagawa no Itto sanken ga “jibanchinka wa Arakawa kakō kara kita Kantō ni kake, sūhyaku nenkan ni tamatta chikasui kumi age[…]”According to Tokyo, Chiba, Saitama, and Kanagawa metropolitan officials, “Subsidence from the mouth of the Arakawa river to northern Kanto is the result of accumulated groundwater seepage over hundreds of years”