Cape Crillon is the southernmost point of Sakhalin Island in Russia. The cape was named by Frenchman Jean-François de La Pérouse, who was the first European to discover it. Cape Sōya in Japan is located 43 km to the south, across La Pérouse Strait.
La Pérouse Strait
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 42 km long and 40 to 140m deep. The narrowest part of the strait is in the west between Russia's Cape Krillion and Japan's Cape Sōya, which is also the shallowest at only 60 meters 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, 8 miles southeast of the Cape Krillion. 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 it 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.