ヘンダーソン基地艦砲射撃
Oka commanded a portion of Japanese troops from the 35th Infantry Brigade in a losing effort during the Battle of Edson's Ridge in September, 1942. He later successfully defended the Matanikau River area during the September, 1942 Matanikau action. During the Battle for Henderson Field, he led the 1,200 troops of the 124th Infantry Regiment across the Matanikau and attacked U.S. Marine defenses early on October 26, 1942, but his attack was thrown back with heavy losses to his men, contributing to the overall decisive Japanese defeat in this battle.