The four major islands of Japan are Honshu, Hokkaido, Kyusha, and Shikoku. The island of Honshu is referred to as the mainland because it is the largest. Edit
When and why was the IWC formed? The IWC, which stands for the International Whaling Commission, was formed on December 2nd, 1946 in order to âprovide for the proper conservation of whale stocks and thus make possible the orderly development of the whaling industryâ (http://iwc.int/history-and-purpose)
The charter stated that before it would come into effect, it must be ratified by the Governments of the Republic of China, France, the USSR, the United Kingdom, and the United States, and by a majority of the other 46 signatories. This occurred on 24 October 1945, and the United Nations was officially formed.