 As the battle on the ridge took place , <unk> 's <unk> and <unk> units also attacked the Marine defenses on the east and west sides of the <unk> perimeter . The <unk> battalion — led by Major Takeshi <unk> — attacked the southeastern sector of the <unk> perimeter , defended by Marines of the 3rd Battalion , 1st Marine Regiment ( 3 / 1 ) . <unk> 's attack started around midnight , with one company attacking through Marine artillery fire and engaging in hand @-@ to @-@ hand combat with the Marine defenders before being thrown back . <unk> was killed in the attack . After <unk> , the Marines , believing that the rest of <unk> 's battalion was still in the area , sent forward six light tanks without infantry support to sweep the area in front of the Marine lines ; four Japanese 37 mm ( 1 @.@ 46 in ) anti @-@ tank guns destroyed or disabled three of them . After abandoning their burning tanks , several of the disabled tanks ' <unk> were <unk> and killed by the Japanese . One tank <unk> down an embankment into the <unk> River , drowning its crew . 
