 The defences were centred on the Okabe Detachment, a brigade-sized force from the 51st Division under Major General Toru Okabe.In January 1943, the Okabe Detachment was defeated in an attack on the Australian base of Wau, about 40 kilometres (25 mi) away.Allied commanders turned their attention to Salamaua, which could be attacked by troops flown into Wau.