Sakhalin is separated from the mainland by the narrow and shallow Strait of Tartary or Mamiya Strait, which often freezes in winter in its narrower part, and from Yezo (Japan) by the Strait of La Perouse.
Whereas in Tokyo the number of frosty nights during a year does not average much over 60, the corresponding number in Sapporo on the north-west of Yezo is 145.
In North Hondo the great Bandai arc forms the axis of the island and stretches into Yezo (HokkaidO).
Those in the neighbourhood of Semipalatinsk may be instanced in the first case and those in the island of Yezo in the second.
Finding himself in command of a squadron which represented practically the whole of Japan's naval forces, he refused to acquiesce in the deposition of the Shogun, his liege lord, and, steaming off to Yezo (1867), proclaimed a republic and fortified Hakodate.
In the northern half of the main island, in Yezo and in the Kuriles, the cold is severe during the winter, which lasts for at least four months, and snow falls sometimes to great depths.
A comparison of the force habitually developed by the wind in various parts of the islands shows that at Suttsu in Yezo the average strength is 9 metres per second, while Izuhara in the island Tsu-shima, Kumamoto in KiOshi and Gifu in the east centre of the main island stand at the bottom of the list with an average wind velocity of only 2 metres.
In the main island the black bear (kuma, Ursusjaponicus) alone has its habitation, but the island of Yezo has the great brown bear (called shi-guma, oki-kuma or aka-kuma), the grisly of North America.
There are six large islands, namely Sakhalin (called by the Japanese Karafuto); Yezo or Ezo (which with the Kuriles is designated Hokkaido, or the north-sea district); Nippon (the origin of the sun), which is the main island; Shikoku (the four provinces), which lies on the east of Nippon; KiUshi or Kyushu (the nine provinces), which lies on the south of Nippon, and Formosa, which forms the most southerly link of the chain.