Thomas Blakiston, a nineteenth-century English explorer and naturalist, noticed that animals in Hokkaido were related to northern Asian species, whereas those on Honshu were related to species from southern Asia. The Tsugaru Strait was established as a zoogeographical boundary, which became known as the Blakiston Line.
Wheat, rather than rice, is grown on Hokkaido.
The Kurile Islands, running northeast from Hokkaido towards the Kamchatka peninsula, are mainly Russian. The Aleutian Islands, running west from Alaska towards Kamchatka, are mainly American.