is a river in

Hokkaidō is Japan's second largest island and comprises the largest and northernmost prefecture, making up its own region. The Tsugaru Strait separates Hokkaidō from Honshu; the two islands are connected by the undersea railway Seikan Tunnel. The la ...

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

Etymology

In 1820, the explorer Takeshiro Matsuura (松浦武四郎) proposed "Tokachi" as the name of the surrounding

Tokachi Province was a short-lived province in Hokkaidō. It corresponded to modern-day Tokachi Subprefecture. History In 1820, the explorer Takeshiro Matsuura (松浦武四郎) proposed Tokachi as the name of the province. The province was named after the To ...

, with each character corresponding to a Japanese homophone. The province was named after this river, which in turn was derived from the

Ainu language Ainu (, ), or more precisely Hokkaido Ainu, is a language spoken by a few elderly members of the Ainu people on the northern Japanese island of Hokkaido. It is a member of the Ainu language family, itself considered a language family isolate ...

word "tokapci". Although the exact origins of "tokapci" were unknown, Hidezo Yamada, an Ainu language researcher, proposed these origins: * tokap-usi ("breast, somewhere") * toka-o-pci ("swamp, around a place, either") Rivers of Hokkaido Rivers of Japan {{Japan-river-stub