YEZO, the most northerly of the five principal islands form ing the Japanese empire, the five being Yezo, Hondo, Shikoku, Kyushu and Formosa. It is situated between 3o' and 41° 21' N. and between 146° 7' and 139° II' E.; its coast-line measures 1,423.32 m., and it has an area of 30,148.41 square miles. On the north it is separated from Sakhalin by Soya Strait (La Perouse) and on the south from Nippon by Tsugaru Strait. Its northern shores are washed by the Sea of Okhotsk, its southern and eastern by the Pacific Ocean, and its western by the Sea of Japan.
Orography.—The highest mountain in the island is Ishikari dake (6,955 ft.) and the next in importance is Tokachi-dake (6,541 ft.). Yubari-take in Ishikari has a height of 6,508 ft., and in the province of Kushiro are 0-akan-dake (4,470 ft.) and Meakan-take (4,500 ft.). Near Hakodate are two conspicuous volcanic peaks, Komaga-take (3,822 ft.) and Tokatsu-dake (3,800 ft.); and 24 m. from Kushiro (by rail) is a volcano called Atosa nobori, or Iwo-zan (sulphur mountain), whence great quantities of first-rate sulphur are exported to the United States. Rishiri, an islet on the extreme N.W., has a peak of the same name rising to 6,000 ft.
Rivers.—Yezo boasts the largest river in the Japanese empire, the Ishikari-gawa, which is estimated to measure 275 m. Its other large rivers are the Teshio-gawa (192 m.), the Tokachi-gawa (120 m.), the Shiribeshi-gawa (88 m.), the Kushiro-gawa (81 m.), the Toshibetsu-gawa (64 m.) and the Yubetsu-gawa (64 m.). The valley of the Ishikari is the most fertile part of the island; the Tokachi is navigable to a point 56 m. from its mouth, but the Teshio has a bar which renders its approach extremely difficult. Nearly all the rivers abound with salmon.
Lakes.—There are no large lakes, the most extensive—Toyako, Shikotsuko and Kushiroko—not having a circumference of more than 25 miles. Lagoons, however, are not uncommon. The larg est of these—Saruma-ko in Kitami—is some 17 m. long by 7 wide. It abounds with oysters nearly as large as those for which the much smaller lagoon at Akkeshi is famous, the molluscs meas uring about 18 in. in length.
Climate.—The climate differs markedly from that of the main island of Japan, resembling rather the climate of the British Isles, though the winter is longer and more severe, and the atmosphere in the warm season contains a greater quantity of moisture. Dur ing five months the country is under snow, its depth averaging about 2 ft. in the regions along the southern coast and more than 6 ft. in the northern and western regions. An ice-drift, setting from the north and working southwards as far as Nemuro, stops all sea trade on the east coast during January, February and March, though the west coast is protected by the warm current of the Kuro-shiwo. Fogs prevail along the east coast during the summer months, and it is not uncommon to find a damp, chilly atmosphere near the sea in July, whereas, a mile inland, the thermometer stands at 8o° or 90° F in the shade, and magnolia trees are in full blossom.
Fauna.—Tsugaru Strait has been shown to form a line of zoological division. Pheasants and monkeys are not found on the Yezo side of this line, though they abound on Hondo, and, on the other hand, Yezo has grouse and solitary snipe which do not exist in Hondo. The Yezo bear, too, is of a distinct species.
Population.—The island seems to have been originally peo pled by a semi-barbarous race of pit-dwellers, whose modern representatives are to be found in the Kuriles or their neighbours of Kamchatka and Sakhalin. These autochthons were driven out by the Ainu, and the latter, in their turn, succumbed to the Japanese. Yezo and 68 adjacent small islands included in the de partment of Hokkaido had 2,812,335 people in 193o, largely due to emigration from Japan proper to Yezo. Yezo is divided into ten provinces, the names of which, beginning from the south, are Oshima, Shiribeshi, Ishikari, Teshio, Kitami, Iburi, Hidaka, To kachi, Kushiro and Nemuro. Of these, Oshima, Shiribeshi and Ishikari are by far the most important. There are only three towns having a large population, viz., Hakodate (197,252), Sap poro (168,576) and Otaru (144,887).