 The central force's combat ships included the light carrier , the seaplane tenders "Sanyo Maru" and "Sanuki Maru", three light cruisers and 16 destroyers, while the western force contained five heavy cruisers and seven destroyers.In addition, four Japanese fleet carriers (, , and ) and the four battleships were in the theater of operation.The Japanese forces were using Tarakan airfield as a forward airbase by 17 January, and Balikpapan was also captured a week later.