Blackforce consisted of roughly 3,000 men—a brigade-sized unit—but roughly half of them were non-combat soldiers such as cooks, medics and drivers. Blackburn organized his men into three battalions—1st battalion mainly consisting of a preexisting &lt;a href="2/3rd%20Machine%20Gun%20Battalion%20%28Australia%29"&gt;2/3rd Machine Gun Battalion&lt;/a&gt;, 2nd mainly made up of the &lt;a href="2/2nd%20Pioneer%20Battalion%20%28Australia%29"&gt;2/2nd Pioneer Battalion&lt;/a&gt;, and a 3rd battalion made up of engineers, soldiers who escaped the defeat in Singapore, and some additional reinforcements. They were also supported by three batteries of the American &lt;a href="Lost%20Battalion%20%28Pacific%2C%20World%20War%20II%29"&gt;2nd Battalion/131st Field Artillery Regiment&lt;/a&gt;, the only American ground unit in the Dutch East Indies campaign and was commanded by Lt. Col. Blucher S. Tharp. The brigade was further supported by a squadron of fifteen light tanks from the British 3rd Hussars Regiment. The Pioneer Battalion, the best unit in the Blackforce, was placed in the front line of Leuwiliang's defenses (east bank of the Tjianten River) with two companies defending the road and two in reserves, while the Machine Gun Battalion was stationed in the flanks and in supporting positions.