Wiktionary
n. A strait dividing the Russian island of Sakhalin in the north from the Japanese island of Hokkaido, and connecting the Sea of Japan on the west with the Sea of Okhotsk on the east.
Wikipedia
La Pérouse Strait, or Sōya Strait, is a strait dividing the southern part of the Russian island of Sakhalin (Karafuto) from the northern part of the Japanese island of Hokkaidō, and connecting the Sea of Japan on the west with the Sea of Okhotsk on the east.
The strait is long and deep. A small rocky island, appropriately named Kamen Opasnosti (Russian for "Rock of Danger") is located in the Russian waters in the northeastern part of the strait. Another small island, Bentenjima, lies near the Japanese shore of the strait.
The strait is named after Jean-François de Galaup, comte de Lapérouse, who explored the channel in 1787.
Japan's territorial waters extend to three nautical miles into La Pérouse Strait instead of the usual twelve, reportedly to allow nuclear-armed United States Navy warships and submarines to transit the strait without violating Japan's prohibition against nuclear weapons in its territory.