Which strait separates Japan’s islands of Honshu and Hokkaido?

Tsugaru Strait separates Japan’s islands of Honshu and Hokkaido.

The strait lies between northern Honshu and southern Hokkaido, linking the Sea of Japan with the North Pacific Ocean. Its narrowest part is about 19.5 kilometres wide, and the seabed contains a deep central passage that has historically been important for navigation.

The Seikan Tunnel runs beneath Tsugaru Strait and carries railway traffic between Aomori Prefecture on Honshu and Hokkaido. Opened in 1988, it was the world’s longest undersea tunnel until the Channel Tunnel opened between Britain and France later that year.

Tsugaru Strait is distinct from La Pérouse Strait, which separates Hokkaido from Russia’s Sakhalin Island. It is also different from Kanmon Strait, the much narrower waterway between Honshu and Kyushu in western Japan.