"Haruna" and "Kongō" departed the Hashirajima fleet anchorage on 29 November 1941, to participate in the opening stage of the Pacific War as part of the Southern (Malay) Force's Main Body, under the overall command of Vice-Admiral Nobutake Kondō. On 4 December 1941, the Main Body arrived off the coast of Southern Siam and Northern Malaya, in preparation for the invasion of Siam and the Malayan Peninsula four days later. When Britain's "Force Z"—consisting of the battleship and the battlecruiser —was quickly defeated by Japan's land-based and carrier aircraft, "Haruna"s battlegroup withdrew from Malayan waters. The battlegroup subsequently sortied from Indochina for three days in mid-December to protect a reinforcement convoy traveling to Malaya and again on 18 December to cover the Army's landing at Lingayen Gulf in the Philippines. The Main Body departed Cam Ranh Bay in French Indochina on 23 December bound for Taiwan, arriving two days later.