Battle of the Tenaru, 1942: the first attack on Guadalcanal

Two weeks after the Marines landed, a Japanese colonel marched his men along the coast at night to retake the airfield. At ten past three in the morning his first wave rushed a sandspit at the mouth of a creek, straight into machine guns and a 37mm gun firing canister. By late afternoon his battalion had been surrounded and destroyed, and he was dead by his own hand.²

Background: the airfield at Lunga Point

In July 1942 the Japanese began building an airfield on Guadalcanal, at the southern end of the Solomon Islands. From there their planes could threaten the Allied bases in the New Hebrides and New Caledonia. On 7 August the US 1st Marine Division under Major General Alexander Vandegrift landed and took the airfield almost unopposed, naming it Henderson Field after Major Lofton Henderson, a Marine aviator killed at Midway.³ › The Battle of Midway, 1942

Then the Navy left. In the night of 8 to 9 August a Japanese cruiser force fell on the American and Australian cruisers guarding the anchorage off Savo Island and defeated them, and the transports sailed away before they had been fully unloaded. The Marines were alone on the island, short of supplies and without air cover. Vandegrift drew his force into a perimeter around the airfield, running along some 9,600 yards of shore from the mouth of the Ilu to Kukum, with its eastern flank bent back inland along the west bank of the creek.⁴

Armies and commanders

The Japanese 17th Army at Rabaul, newly put in charge of the ground fighting on Guadalcanal, decided to strike at once. Its first counterstroke was the Ichiki Force: the 2d Battalion of the 28th Infantry, reinforced into a combat team of about 2,000 men under Colonel Kiyono Ichiki. The unit had been meant to land on Midway; after the defeat there it was sent to Guam, and when the Marines landed it was at sea bound for Japan. It was turned around and landed at Truk on 12 August.⁵

Ichiki did not wait for the whole of his force. Japanese destroyers of what the Marines came to call the Tokyo Express landed him and his forward echelon, 900 men by the Marine histories, about 1,000 by the Army's, at Taivu Point, some 22 miles east of the Lunga, during the night of 18 August. The rest of his unit was to follow by transport.⁶

Facing him were the infantry battalions of the 1st Marine Division on Guadalcanal, four in line and one in division reserve, with their artillery. The eastern flank, along the west bank of the creek, was held by Lieutenant Colonel Edwin Pollock's 2d Battalion, 1st Marines, of Colonel Clifton Cates's regiment. A 37mm gun covered the sandspit at the creek mouth, but the position there was not wired in.⁷

The battle in phases

Warnings

On 19 August a Marine patrol under Captain Charles Brush ran into a party of Japanese walking openly along the beach near Taivu Point and killed nearly all of them. Their helmets bore the army star, not the anchor and chrysanthemum of the naval landing forces, and their papers included a code for signaling from ship to shore. The Marines now knew that fresh army troops had landed to the east. Ichiki, knowing he had been discovered, decided to attack at once.⁸

On the night of 20 to 21 August Marine listening posts on the east bank heard troops moving in the jungle, exchanged fire and fell back across the river mouth. About the same time Jacob Vouza, a retired sergeant major of the Solomon Islands police who had volunteered to scout for the Marines, staggered into Pollock's command post. The Japanese had caught him, and when he would not talk they had stabbed him and left him for dead. He had freed himself and made his way through their lines to warn the Marines that the attack was coming.⁹

The charge across the sandspit

At 03:10 on 21 August a column of about 200 Japanese rushed the sandspit in a bayonet assault. Rifle and machine-gun fire and a 37mm gun firing canister cut most of them down, but because the position was not wired a few broke into the Marine line and took some emplacements. Pollock's reserve, Company G, counterattacked and threw them back across the river.¹⁰

Ichiki then turned his mortars and 70mm guns on the Marine positions and sent a second company wading out beyond the breakers to come ashore west of the river mouth. It was cut down in the surf by machine guns and canister, while the 75mm pack howitzers of the 3d Battalion, 11th Marines shelled the Japanese gathered on the beach east of the creek.¹¹

Encirclement

At daybreak Pollock reported that he could hold. Vandegrift ordered the division reserve, Lieutenant Colonel Lenard Cresswell's 1st Battalion, 1st Marines, to cross the creek upstream and attack the Japanese from the flank and rear. Cresswell crossed before 07:00 and swung north. By 14:00 the Japanese were penned into the point of land between the creek, the beach and his companies.¹²

Groups of Japanese tried to break out to the east along the beach and were cut down by the encircling companies. The newly arrived fighter pilots of VMF-223 joined in, strafing the men trying to escape.¹³

Turning point: the tanks

To finish the fight before dark, Vandegrift sent a platoon of light tanks across the sandspit at 15:00, into what was now the rear of the Ichiki Force. Firing canister and machine guns, they rolled through the Japanese positions. The histories differ on the cost: Hough's account has two tanks disabled, one by a mine, Zimmerman's counts one tank lost, and the Army history speaks of light damage to two. By 17:00 it was over.¹⁴

Aftermath

The toll was lopsided. The 1958 Marine Corps history counts nearly 800 Japanese killed; Zimmerman's 1949 monograph records almost total casualties in a group of about 900, and the Army history almost 800 casualties. The Marine histories count 15 prisoners; the Army history says one man surrendered and 14 were captured. Only a few escaped into the jungle. The Marines lost 34 killed by their count, 35 by the Army's, and 75 wounded. The battlefield yielded ten heavy and twenty light machine guns, 700 rifles, three 70mm guns and twelve flamethrowers that had never been used. Ichiki, the histories agree, committed suicide.¹⁵

The second echelon of his force never reached the island as planned. Its transports, with about 1,500 men, sailed under the cover of a powerful fleet. In the Battle of the Eastern Solomons on 24 August American carrier planes wrecked the light carrier Ryujo; the next day aircraft from Henderson Field and Army B-17s struck the convoy, and it turned back.¹⁶ › The Guadalcanal Campaign, 1942 to 1943

Legacy and memory

The Tenaru was a small battle by the standards of the Pacific war, but it was the first time the Japanese army tried to retake Guadalcanal on land, and it failed. John Miller, the Army's historian, judged that the small force Ichiki threw at the Marines showed either defective intelligence or sublime confidence, and that he must have held the Marines in complete contempt. The pattern it set held for months: Japanese forces landed piecemeal and thrown against the perimeter, and Marine firepower holding the airfield on which everything depended. The campaign ended only in February 1943, with the Japanese evacuation of the island.¹⁷

Even the name of the battle is a mistake. The Marines' maps confused the streams east of the Lunga. The Marine Corps and Army histories call the creek where the battle was fought the Ilu or Alligator Creek; the real Tenaru lies farther east. The battle kept the wrong name.¹⁸

Jacob Vouza became one of the heroes of the campaign. He survived his wounds, and the United States awarded him the Silver Star for his heroism.¹⁹ › Carlson's Long Patrol, 1942