Oka 's unit of about 650 men attacked the Marines at several locations on the west side of the Lunga perimeter . At about 04 : 00 on 14 September , two Japanese companies attacked positions held by the 3rd Battalion , 5th Marine Regiment ( 3 / 5 ) near the coast and were thrown back with heavy losses . Another Japanese company captured a small ridge somewhat inland but was then pinned down by Marine artillery fire throughout the day and took heavy losses before withdrawing on the evening of 14 September . The rest of Oka 's unit failed to find the Marine lines and did not participate in no attack .