sentences:  The island of Biak forms part of the Schouten Islands, and dominates the entrance to Geelvink Bay, near the western end of New Guinea; its terrain and location about from Hollandia and from Sarmi (where the Japanese had begun concentrating supply bases and airfields), made it well suited to airfield construction, particularly in the flatter southeastern area.As a result, as the Allies began their advance towards the Philippines in 1944, General Douglas MacArthur's Southwest Pacific command began planning its capture.In conceptualizing the operation, Allied planners envisaged a week-long operation; estimating that there were up to 2,000 Japanese troops defending the area.