In his classic account, Guadalcanal Diary, author Richard Tregaskis witnessed the deadly duel: “It was fascinating to see them bustling amongst the trees, pivoting, turning, spitting sheets of yellow flame. It was like a comedy of toys, something unbelievable, to see them knocking over palm trees, which fell slowly, flushing the running figures of men from underneath their treads, following and firing at the fugitives. It was unbelievable to see men falling and being killed so close, to see the explosions of Jap grenades and mortars, black fountains and showers of dirt near the tanks, and see the flashes of explosions under their very treads. We had not realized there were so many Japs in the grove. Group after group was flushed out and shot down by the tanks’ canister shells.”
With no antitank weapons, the Japanese were forced to stop the tanks by utilizing anti-tank mines and grenades. Ichiki’s men took heavy losses attempting to halt the Stuarts using these primitive means. Case’s “steel beasts” were ripping into the enemy when he received word from Cates to move back. Engrossed in his work eliminating the Japanese positions, Case snapped, “Leave us alone. We are too busy killing Japs.” For hours the deafening sounds of automatic weapons fire permeated the air.
Miraculously, several men survived the onslaught. One sergeant, Sadanobu Okada, remained motionless as a pair of Stuarts neared him. The lead vehicle passed over him, but he escaped injury because he was shielded by the enormous root of a coconut tree. He stayed in this position until nightfall, when he slipped away.
Other members of Okada’s unit were not so lucky. Numerous Japanese fled to the ocean only to be cut down by the Marine rifle fire. Other enemy infantrymen made their way to the east and south. But, they too, were killed. Wildcat fighters from VMF-223 patrolled the beach area, gunning down escaping Japanese with their M2 12.7mm Browning machine guns. By late in the afternoon of August 21, the Battle of the Tenaru River was finished.
The final demise of Colonel Ichiki is still shrouded in obscurity. One account says he committed hara-kiri after putting a torch to his regiment’s flag. Another possibility is that he was killed during mop-up operations after the majority of the fighting had ceased. The few enemy survivors, however, insist he was lost leading his men in a charge across the sand spit.
Regardless of how he met his end, Ichiki’s plan to annihilate the Marines was a disaster. He thoughtlessly sent his men into combat knowing he was outnumbered nearly three to one. He also attacked the leatherneck positions in the Lunga area knowing they were well entrenched there. As the Marine Corps history states: “Ichiki’s mission was suicidal in concept, execution, and outcome.”
When it was over, nearly 800 Japanese were massacred and only 15 were taken prisoner. The Marines suffered 34 dead and another 75 wounded. Vandegrift’s men also snared several 70mm guns, nearly two dozen Nambu machine guns, another 20 mortars, a dozen flamethrowers, 700 Arisaka rifles, plus a variety of other weapons and ammunition.
When news of the slaughter of the Ichiki detachment reached headquarters, one Japanese general commented, “I think it’s a false report.” When the news was confirmed, the Japanese officers present were in total disbelief. The invincibility of the mighty Imperial Army had been shattered. The “haughty, effeminate and cowardly” Americans had dealt a severe blow to the morale of the Japanese fighting man.
For the Marines, it was also a learning experience. General Vandegrift penned a letter to the Commandant of the Marine Corps, Maj. Gen. Thomas Holcomb, in which he wrote, “General, I have never heard or read of this kind of fighting. These people refuse to surrender. The wounded wait until men come up to examine them … and blow themselves and the other fellow to pieces with a hand grenade.”
The Battle of the Tenaru (Ilu) would set the stage for combat in the Pacific Theater—bloody and unforgiving. As Brig. Gen. Samuel B. Griffith commented in his book The Battle for Guadalcanal, “But there was something more fundamental involved here than action taken on the basis of poor information, a reckless and stupid colonel, dedicated soldiers, and a disparity in weapons. This was “face.” Once he committed his sword, Ichiki must conquer with it or die. This was the code of the Samurai, ‘The Way of the Warrior:’ Bushido.
“For their part, the Marines had learned one lesson they would not forget. From this morning until the last days of Okinawa, over two and a half years later, they fought a ‘no quarter’ war. They asked none for themselves. They gave none to the Japanese.”
Al Hemingway is a Vietnam veteran of the U.S. Marine Corps. He is a frequent contributor to WWII History and resides in Connecticut.
Originally Published in 2018.