The Battle of Hollandia (code-named Operation Reckless) was an engagement between American and Japanese forces during World war II. It took place in spring of 1944 and was part of the New Guinea campaign. The landings were undertaken simultaneously with the amphibious landings at Aitape ("Operation Persecution") to the east. The battle was an unqualified success for the US forces, resulting in a withdrawal by the Japanese to a new strategic defence line in the west of New Guinea and the abandonment of all positions in the east of the island.