is a channel

Channel (geography)

In physical geography, a channel is the physical confine of a river, slough or ocean strait consisting of a bed and banks.A channel is also the natural or human-made deeper course through a reef, sand bar, bay, or any shallow body of water...

 between Honshu

Honshu

is the largest island of Japan. The nation's main island, it is south of Hokkaido across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyushu across the Kanmon Strait...

 and Hokkaido

Hokkaido

, formerly known as Ezo, Yezo, Yeso, or Yesso, is Japan's second largest island; it is also the largest and northernmost of Japan's 47 prefectural-level subdivisions. The Tsugaru Strait separates Hokkaido from Honshu, although the two islands are connected by the underwater railway Seikan Tunnel...

 in northern Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 connecting the Sea of Japan

Sea of Japan

The Sea of Japan is a marginal sea of the western Pacific Ocean, between the Asian mainland, the Japanese archipelago and Sakhalin. It is bordered by Japan, North Korea, Russia and South Korea. Like the Mediterranean Sea, it has almost no tides due to its nearly complete enclosure from the Pacific...

 with the Pacific Ocean

Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

. It was named after the western part of Aomori Prefecture

Aomori Prefecture

is a prefecture of Japan located in the Tōhoku Region. The capital is the city of Aomori.- History :Until the Meiji Restoration, the area of Aomori prefecture was known as Mutsu Province....

. The Seikan Tunnel

Seikan Tunnel

The Seikan Tunnel is a railway tunnel in Japan, with a long portion under the seabed. Track level is about below seabed and below sea level. It travels beneath the Tsugaru Strait—connecting Aomori Prefecture on the Japanese island of Honshu and the island of Hokkaido—as part of the Kaikyo Line...

 passes under it at its narrowest point (19.5 km) between Tappi Misaki on the Tsugaru Peninsula

Tsugaru Peninsula

The is a peninsula in Aomori Prefecture, at the northern end of Honshū island, Japan. The peninsula projects north into the Tsugaru Strait separating Honshū from Hokkaidō. The western coast is on the Sea of Japan, while on its eastern coast are Aomori Bay and Mutsu Bay...

 in Aomori

Aomori Prefecture

is a prefecture of Japan located in the Tōhoku Region. The capital is the city of Aomori.- History :Until the Meiji Restoration, the area of Aomori prefecture was known as Mutsu Province....

, Honshū and Shirakami Misaki on the Matsumae Peninsula in Hokkaidō.

Japan's territorial waters extend to three nautical miles (5.6 km) into the strait instead of the usual twelve, reportedly to allow nuclear

Nuclear weapon

A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission bomb test released the same amount...

-armed United States Navy

United States Navy

The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

 warships and submarines to transit the strait without violating Japan's prohibition against nuclear weapons in its territory.

The Tsugaru Strait has eastern and western necks, both approximately 20 km across with maximum depths of 200 and 140 m respectively.

In the past, the most common way for passengers and freight to cross the strait was on ferries, approximately a four-hour journey. Now the Seikan Tunnel

Seikan Tunnel

The Seikan Tunnel is a railway tunnel in Japan, with a long portion under the seabed. Track level is about below seabed and below sea level. It travels beneath the Tsugaru Strait—connecting Aomori Prefecture on the Japanese island of Honshu and the island of Hokkaido—as part of the Kaikyo Line...

 provides a convenient but more expensive alternative and approximately halves the travel time in comparison to ferrying. When Shinkansen trains

Hokkaido Shinkansen

The is a high-speed rail line currently under construction between Aomori and Hokkaido through the Seikan Tunnel. Construction started in May 2005, and the initial Shin-Aomori to Shin-Hakodate section is projected to open in 2015. There are long-term plans to extend the line to Sapporo...

 can traverse the tunnel to Hakodate (scheduled for 2015), the journey time will be cut to 50 minutes.

On September 26, 1954 1,172 lives were lost when the ferry Tōya Maru

Toya Maru

The was a Japanese train ferry constructed by the Japanese National Railways which sank during a typhoon in the Tsugaru Strait between the Japanese islands of Hokkaidō and Honshū on September 26, 1954. It is said that 1,153 people aboard were killed in the accident...

sank in the strait.

Thomas Blakiston

Thomas Blakiston

Thomas Wright Blakiston was an English explorer and naturalist.Born in Lymington, Hampshire, England, Blakiston was the son of Major John Blakiston, second son of Sir Matthew Blakiston, 2nd Baronet...

, an English explorer and naturalist, noticed that animals in Hokkaido were related to northern Asian species, whereas those on Honshu to the south were related to those from southern Asia. The Tsugaru Strait was therefore established as a major zoogeographical boundary, and became known as the "Blakiston Line".