Capture of Netherlands East Indies
Netherlands East Indies including Borneo, Sumatra and Java yielded much more oil than Japanese demand, together with iron, bauxite and coal. The area was a critical target to capture for Japan to overcome economic sanction by Western powerful countries.
Conquest of Netherlands East Indies was initiated by Japanese army's disembarkation at Borneo Island on January 10th, 1942. Wading through the wide jungle, it occupied the main area by February. However, the oil facilities were destroyed by withdrawn Dutch army.
In turn, Japanese army quickly captured Sumatra island by parachute troopers and acquired intact main refineries by February 20th.