 The terrain upon which the Australians advanced hampered their movement considerably . Consisting mainly of steep " razor @-@ back " ridges and thick jungle which restricted the tactics that Whitehead could employ , the 26th Brigade mainly employed infiltration tactics , advancing on " narrow fronts " using columns of troops consisting of an infantry company forward , followed by a troop of tanks with an engineer section in support . Initially the Japanese were surprised by the presence of the Matilda tanks as their noise had been masked by the artillery and rocket barrage , and a number of positions were abandoned by Japanese soldiers who were put to flight upon seeing the tanks , however , as the day progressed the opposition stiffened and the defenders recovered after the initial shock . Progress subsequently became very slow , and as the 2 / 48th Battalion approached " Coconut Ridge " ( designated Highland 5 by the Japanese ) at around midday , one of the Matildas was disabled when it lost a track to an improvised explosive device which had been placed under the road by the defending Japanese . With the tanks isolated from their infantry support , a small Japanese team advanced from cover to attack a second tank which had come up to support the first , and taking the machine gunner by surprise , they placed an explosive charge in front of it . Although the resulting explosion did not knock the tank out of action , it trapped its crew inside for the rest of the day . 
