 At the same time as the first battle at Mubo, the Australian 24th Infantry Battalion, which had been defending the Wampit Valley in an effort to prevent Japanese movement into the area from Bulolo, detached several platoons to reinforce the 2/3rd Independent Company.During the month of May, they were heavily engaged in patrolling the 3rd Division's northern flank, around the Markham River, and the area around Missim, and one patrol succeeded in reaching the mouth of the Bituang River, to the north of Salamaua.In response to the Allied moves, the Japanese Eighteenth Army commander, Lieutenant General Hatazō Adachi, sent the 66th Infantry Regiment from Finschhafen to reinforce the Okabe Detachment and launch an offensive.