The Great Okarian Offensive of Winter was the first phase of Space War. It was basically the invasion of Federation of Lactia and Pluto and allies by their neighbor Okarian Empire. It began with the attack to Yhoron. After this, Okarian Empire began to win many battles, reaching the solar system of Istara Group and Camusa Alpha. The plan included an invasion of Kingdom of Dimmin if it tries to support its ally (Federation of Lactia). However, Kingdom of Dimmin did not support to the federation (secret treaty with Pluto: Division and Annexation of the Federation), and the attack to the kingdom was delayed (fatal error: an offensive against the kingdom at this critical moment would have been won the war for the Empire), leading to the concentration of the main okarian armies in Istara Group