During the day of 12 September , Kawaguchi 's troops struggled through the jungle toward their assembly points for that night 's attacks . Kawaguchi wanted his three Center Body battalions in place by 14 : 00 , but they did not reach their assembly areas until after 22 : 00 . Oka was also delayed in his advance towards the Marine lines in the west . Only the Kuma battalion reported that they were in place on time . Despite the problems in reaching the planned attack positions , Kawaguchi was still confident in his attack plan because a captured U.S. pilot disclosed that the ridge was the weakest part of the Marine defenses . Japanese bombers attacked the ridge during daytime on 11 – 12 September , causing a few casualties , including two killed .