The Japanese invasion of Lingayen Gulf (Filipino: Paglusob ng mga Hapones sa Golfo ng Lingayen) was the key point in the Japanese plan for the conquest of the Philippines. Preparations had already been made by the Attack on Clark Field and the landings of Japanese forces at five points in northern and southern Luzon and Mindanao in early/mid December 1941, with the IJAAF seizing air fields and basing aircraft for ground support, and the Imperial Japanese Navy establishing seaplane bases at the Camiguin Island, Legaspi, and Davao. The main landing of Japanese forces targeted Lingayen Gulf, with its proximity to the Philippine capital of Manila, and Lamon Bay on the opposite coast to the south. The Japanese order of battle The Japanese invasion force of 43,110 men was under the overall command of the IJA 14th Area Army under General Masaharu Homma. The force contained the IJA 48th Division (less the Tanaka and Kanno Detachments which had already landed in the invasions of Aparri and Vigan) under Lt General Yuitsu Tsuchihashi. A newly formed division from Taiwan, it lacked combat experience, but it was the best equipped and motorized division in the Japanese Army. It also contained elements of the IJA 16th Division including the 4th and 7th Tank Regiments with a total of between 80 and 100 tanks, and by three field artillery regiments. The invasion force sailed in three convoys, each of which constituted a separate task force with a separate landing point and objective. The Japanese maintained strict internal secrecy and only senior commanders were aware of the targets. The first task force, known as the Kamijama Detachment, consisted of the IJA 9th Infantry Regiment in 21 transports. It departed Keelung in northern Taiwan on the morning of 17 December escorted by the same fleet used in the Japanese invasion of Batan Island. The second task force with the 1st Formosa Regiment of the IJA 48th Division and 7th Tank Regiment in with 28 transports departed at noon 18 December from Mako in the Pescadores Islands. It was escorted by the same ships which previously escorted by the Vigan invasion force. The third task force had the 47th Infantry Regiment of the 48th Division and 4th Tank Regiment, departed Takao on Taiwan the evening of 18 December. It was escorted by the same ships which had previously escorted the Aparri invasion force. Distant cover was provided by