The Battle of Tarakan was the first stage in the Borneo campaign of 1945. It began with an amphibious landing by Allied forces on 1 May, code-named Operation Oboe One; the Allied ground forces were drawn mainly from the Australian 26th Brigade, but included a small element of Netherlands East Indies personnel. The main objective of the landing was the capture of the island's airfield. While the battle ended with success for the Allied forces over the Japanese defenders, this victory is generally regarded as having not justified its costs. The airfield was so heavily damaged that it ultimately could not be repaired in time to make it operational for other phases of the Allied campaign in Borneo. Background Geography Tarakan is a triangle-shaped island off the coast of Borneo. The island is roughly long from its northernmost point to the southern tip and wide towards the north of the island. The small island of Sadau is located about off Tarakan's west coast. Almost all of Tarakan's coastline is swampy, and in 1945 mangroves on the northern half of the island stretched to inland. The coastal mangroves in the southern portion of the island were narrower. Inland from the swamps, most of central Tarakan comprised a series of steep and densely forested hills just over high. Tarakan is located three degrees north of the equator and has a tropical climate. The maximum temperature for most days is about , and relative humidity is consistently high at about 90 percent. In 1945, Tarakan Town was the main settlement of the island. This town was located inland, and was separated from the south-west coast by several small hills covered in low vegetation. Four piers used to dock oil tankers were located on this coastline at the settlement of Lingkas, and were connected to Tarakan Town by three surfaced roads. Tarakan airfield was located about north-west of Tarakan Town. Of the island's two oilfields, Sesanip Oilfield was located at the north-east edge of the airfield while the larger Djoeata or Juata Oilfield was to the north. The village of Djoeata was located on Tarakan's north-west coast and linked to Djoeata Oilfield by a track. Japanese occupation Prior to World War II, Tarakan formed part of the Netherlands East Indies (NEI) and was an important oil production centre. The island's two oilfields produced 80,000 barrels of oil per month in 1941. Securing Tarakan's oilfields