Actions along the Matanikau

Map of the Matanikau Action, 23–23 September. Green represents U.S. Marine units and movements and red Japanese positions and actions. Point Cruz is misidentified as "Koli Point" and the destroyer USS Monssen that supported the operation is misidentified as USS Ballard.

The U.S. Marine plan called for Puller's battalion to march west from the Lunga perimeter, scale a large terrain feature called Mount Austen, cross the Matanikau River, and then reconnoiter the area between the Matanikau and Kokumbona village. At the same time, the 1st Raider Battalion—now under the command of Lieutenant Colonel Samuel B. Griffith—was to cross at the mouth of the Matanikau to explore the area between the river, Kokumbona, and further west towards Tassafaronga. The Marines thought that there were about 400 Japanese in that area.[21][22][23]

The actual number of Japanese troops in the Matanikau Valley was much higher than the Marine estimate. Believing that the Allies might attempt a major amphibious landing near the Matanikau River, Kawaguchi assigned Oka's 124th Infantry Regiment—numbering about 1,900 men—to defend the Matanikau. Oka deployed his "Maizuru" Battalion around the base of Mount Austen and along the west and east banks of the Matanikau River. The rest of Oka's force was located west of the Matanikau, but in position to respond quickly to any Allied attacks in that area. Including other Japanese troops located near Kokumbona, total Japanese forces in the general Matanikau area numbered about 4,000.[24][25][26]

The 930 men of Puller's battalion marched west from the Lunga perimeter early on the morning of 23 September. Later that morning, Puller's troops chased away two Japanese patrols that were reconnoitering the Marine Lunga defenses. Puller's battalion then camped for the night and prepared to climb Mount Austen the next day.[27]

At 17:00 on 24 September, as Puller's men hiked up the northeast slope of Mount Austen, they surprised and killed a bivouac of 16 Japanese soldiers. The noise from the skirmish alerted several companies of Oka's Maizuru Battalion, who were emplaced nearby. The Maizuru troops quickly attacked Puller's Marines, who took cover and returned fire. Acting on Oka's orders, the Japanese slowly disengaged while withdrawing towards the Matanikau River, and the engagement was over by nightfall. The Marines counted 30 dead Japanese and had suffered 13 dead and 25 wounded. Puller radioed headquarters and requested help to evacuate the wounded. Vandegrift replied that he would send the 2nd Battalion, 5th Marine Regiment (2/5) as reinforcements the next day.[28]

U.S. Marine Lieutenant Colonel Lewis "Chesty" Puller on Guadalcanal in September 1942

2/5—under Lieutenant Colonel David McDougal—rendezvoused with Puller's unit early on 25 September. Puller sent his casualties back to the Lunga perimeter with three companies of his battalion and continued on with the mission with his remaining company (Company C), his headquarters staff, and 2/5, and they bivouacked for the night between Mount Austen and the Matanikau River.[29]

On the morning of 26 September, Puller and McDougal's troops reached the Matanikau River and attempted to cross over a bridge previously built by the Japanese that was called the "one-log bridge". Because of resistance by about 100 Japanese defenders around the bridge, the Marines instead proceeded north along the east bank of the Matanikau to the sand spit on the coast at the mouth of the river. Oka's troops repulsed a Marine attempt to cross the Matanikau at the sand spit as well as another attempt to cross the one-log bridge later in the afternoon. In the meantime, Griffith's Raider battalion—along with Merritt A. Edson, commander of the 5th Marine Regiment—joined Puller and McDougal's troops at the mouth of the Matanikau.[30]

A view of the Point Cruz area looking south. The three companies from Puller's battalion landed just to the right of Point Cruz as seen in the picture (bottom foreground) and occupied Hill 84 (marked with an "X") before being surrounded by Japanese forces.

Edson brought with him a "hastily devised" plan of attack—primarily written by Lieutenant Colonel Merrill B. Twining, a member of Vandegrift's division staff—that called for Griffith's Raiders—along with Puller's Company C—to cross the one-log bridge and then outflank the Japanese at the river mouth/sand spit from the south. At the same time, McDougal's battalion was to attack across the sand spit. If the attacks were successful, the rest of Puller's battalion would land by boat west of Point Cruz to take the Japanese by surprise from the rear. Aircraft from Henderson Field—as well as Marine 75 mm (2.95 in) and 105 mm (4.1 in) artillery—would provide support for the operation. The Marine offensive would begin the next day, on 27 September.[31]

The Marine attack on the morning of 27 September did not make much headway. Griffith's Raiders were unable to advance at the one-log bridge over the Matanikau, suffering several casualties, including the death of Major Kenneth D. Bailey and the wounding of Griffith. A flanking attempt by the Raiders further upstream also failed. The Japanese, who had reinforced their units at the mouth of the Matanikau during the night with additional companies from the 124th Infantry Regiment, repulsed the attacks by McDougal's men.[32][33]

As a result of "garbled" messages from Griffith because of a Japanese air raid on Henderson Field that disrupted the Marine communications net, Vandegrift and Edson believed that the Raiders had succeeded in crossing the Matanikau. Therefore, Puller's battalion was ordered to proceed with the planned landing west of Point Cruz. Three companies of Puller's battalion, under Major Otho Rogers, landed from nine landing craft just west of Point Cruz at 13:00. Rogers' Marines pushed inland and occupied a ridge, called Hill 84, about 600 yd (550 m) from the landing area. Oka—recognizing the seriousness of this landing—ordered his forces to close on Rogers' Marines from both the west and east.[34]

Map overlay on an aerial photo of the Point Cruz area showing the U.S. Marine retreat from the ridge (center) to the coast for withdrawal by landing craft (black arrow). The shaded areas represent the Japanese positions. The destroyer USS Monssen that supported the withdrawal is misidentified as the USS Ballard in this picture.

Soon after occupying the ridge, Rogers' men came under heavy fire from two directions from Oka's forces. Major Rogers was hit by a mortar shell and died instantly. Captain Charles Kelley—commander of one of the companies—took command and deployed the Marines in a perimeter defense around the ridge to fight back.[35][36] The Marines on Hill 84 were without radio communication and thus could not call for help. The Marines improvised by using white undershirts to spell out the word "H-E-L-P" on the ridge. A Cactus Air Force (the name for the Allied aircraft operating out of Henderson Field) SBD Dauntless supporting the operation spotted the undershirt message and relayed the message to Edson by radio.[37]

Paul Moore Jr., a Marine veteran who participated in the battle, described it:

Each... [platoon] was to run across the sandspit until they were opposite the bank, wade across the river, and attack the Japanese battalion, which was dug in with automatic weapons and hand grenades and mortars in the bank.... Well, one platoon went over and got annihilated. Another platoon went over and got annihilated. Then another... we all realized it was insane... But if you're a Marine, you're ordered across the goddamn beach and you go.[38]

Edson received a message from the Raider Battalion reporting their failure to cross the Matanikau. Edson, speaking to those around him, stated, "I guess we better call them off. They can't seem to cross the river." Puller angrily replied, "You're not going to throw these men away!" apparently in reference to his men trapped on the west side of the Matanikau, and "stormed" off toward the beach where, with the help of his personal signalman, Puller was able to hail the Navy destroyer USS Monssen that was supporting the operation. Once aboard Monssen, Puller and the destroyer led 10 landing craft towards Point Cruz and established communications with Kelley on the ridge by signal flag.[39]

By this time, Oka's troops had moved into position to completely cut off the Marines on Hill 84 from the coast. Therefore, Monssen—coordinated by Puller—began to blast a path between the ridge and the beach. After about 30 minutes of firing by the destroyer, the way was clear for the Marines to escape to the beach. Despite taking some casualties from their own artillery fire, most of the Marines made it to the beach near Point Cruz by 16:30. Oka's troops put heavy fire on the Marines at the beach in effort to keep them from successfully evacuating, and the U.S. Coast Guard crews manning the U.S. landing craft responded with their own heavy fire to cover the Marines' withdrawal. Under fire, the Marines boarded the landing craft and successfully returned to the Lunga perimeter, ending the action. U.S. Coast Guard Signalman First Class Douglas Albert Munro—Officer-in-Charge of the group of Higgins boats—was killed while providing covering fire from his landing craft for the Marines as they evacuated the beach and was posthumously awarded the Medal of Honor for the action, to date the only Coast Guardsman to receive the decoration.[40][41]

A painting depicts U.S. Coast Guard landing craft crews covering the evacuation of U.S. Marines under fire near Point Cruz, Guadalcanal on 27 September 1942.

The results of the action were gratifying to the Japanese, still recovering from their defeat at Edson's Ridge two weeks prior. Oka's troops counted 32 bodies of U.S. Marines around Hill 84, and they captured 15 rifles and several machine guns that the Marines left behind. Major General Akisaburo Futami—chief of staff for the 17th Army at Rabaul—noted in his diary that this action was "the first good news to come from Guadalcanal."[42]

The action—described as "an embarrassing defeat" for the U.S. Marines—resulted in "finger-pointing" among the Marine commanders as they sought to attribute blame. Puller blamed Griffith and Edson, Griffith blamed Edson, and Twining blamed Puller and Edson. Colonel Gerald Thomas—Vandegrift's operations officer—blamed Twining. The Marines, however, learned from the experience, and the defeat was the only one of that size suffered by U.S. Marine forces during the Guadalcanal campaign.[43]

The Japanese continued to deliver additional forces to Guadalcanal in preparation for their planned major offensive in late October. Between 1 and 5 October, Tokyo Express runs delivered troops from the 2nd Infantry Division, including their commander, Lieutenant General Masao Maruyama. These troops consisted of units from the 4th, 16th, and 29th Infantry Regiments.[44] In an attempt to exploit the advantage gained in the September Matanikau action, Maruyama deployed the three battalions of the 4th Infantry Regiment with additional supporting units under Major General Yumio Nasu along the west side of the Matanikau River south of Point Cruz with three companies from the 4th Infantry Regiment placed on the east side of the river. Oka's exhausted troops were withdrawn from the immediate Matanikau area. The Japanese units east of the river were to assist in preparing positions from which heavy artillery could fire into the U.S. Marines' perimeter around Lunga Point.[45]

Aware of the Japanese activity around the Matanikau, the U.S. Marines prepared for another offensive in the area with the objective of driving Japanese forces west and away from the Matanikau valley. Applying lessons learned from the September action, this time the Marines prepared a carefully coordinated plan of action involving five battalions: two from the 5th Marine Regiment, two from the 7th Marine Regiment, and one from the 2nd Marine Regiment augmented with Marine scout and sniper personnel (called the Whaling Group after its commander Colonel William J. Whaling). The 5th Marine's battalions were to attack across the mouth of the Matanikau while the other three battalions were to cross the Matanikau inland at the "one-log bridge", turn north, and attempt to trap the Japanese forces between themselves and the coast. This time the Marine division headquarters planned to retain control of the entire operation and carefully arranged detailed support for the operation from artillery and aircraft.[46]

Japanese tanks knocked out by 37 mm guns near the mouth of the Matanikau River, Guadalcanal, October 1942

On the morning of 7 October, the two 5th Marine battalions attacked west from the Lunga perimeter towards the Matanikau. With direct-fire support from 75 mm guns mounted on halftracks, plus additional troops supplied by the 1st Raider Battalion, the Marines forced 200 soldiers from the Japanese 3rd Company, 1st Battalion, 4th Infantry into a small pocket on the east side of the Matanikau about 400 yd (370 m) from the river mouth. The Japanese 2nd Company tried to come to the aid of their comrades in the 3rd Company but were unable to cross the Matanikau and took casualties from Marine gunfire. Meanwhile, the two 7th Marine battalions and the Whaling Group reached positions east of the one-log bridge unopposed and bivouacked for the night.[47]

Oblivious of the U.S. Marine offensive, General Nasu sent the 9th Company of the 4th Infantry Regiment's 3rd Battalion across the Matanikau on the evening of 7 October. The Japanese regimental commander received word of the U.S. Marine operation about 03:00 on 8 October and immediately ordered his 1st and 2nd battalions closer to the river to counter the Marine operation.[48]

Map of the U.S. Marine offensive around the Matanikau, 7–9 October 1942

Rain on 8 October slowed the U.S. 7th Marines and the Whaling Group as they attempted to cross the Matanikau. Near evening the U.S. 3rd Battalion 2nd Marines reached the first ridge west of the Matanikau about 1 mi (1.6 km) from Point Cruz. Opposite their position on the east bank of the river, Company H from the U.S. 2nd Battalion 7th Marines unknowingly advanced into an exposed position between the Japanese 9th Company on the east bank and the rest of the Japanese 3rd Battalion on the west bank and was forced to withdraw. As a result, the Marines halted their attack for the night and prepared to resume it the next day. Unaware that the Marines threatened their positions on the west bank of the Matanikau, the Japanese commanders—including Maruyama and Nasu—ordered their units to hold in place.[49]

During the night, the survivors of the Japanese 3rd Company, about 150 men, attempted to break out of their pocket and cross the sandbar at the mouth of the Matanikau. The 3rd Company soldiers overran two platoons from the 1st Raiders, who were not expecting an attack from that direction, and the resulting hand-to-hand melee left 12 Marines and 59 Japanese dead. The remaining 3rd Company survivors were able to cross the river and reach friendly lines. According to Frank J. Guidone, a Marine participant in the engagement, "The fight was hours of hell. There was yelling, screams of the wounded and dying; rifle firing and machine guns with tracers piercing the night—(a) combination of fog, smoke, and the natural darkness. Truly an arena of death."[50]

On 9 October, Puller's battalion—located on the ridge marked with a red "A"—trapped the Japanese 2nd Battalion, 4th Infantry in the wooded ravine, marked with a red "B".

On the morning of 9 October, the U.S. Marines renewed their offensive west of the Matanikau. The Whaling Group and the 2nd Battalion 7th Marines—commanded by Lieutenant Colonel Herman H. Hanneken—reached the shoreline around Point Cruz and trapped large numbers of Japanese troops between themselves and the Matanikau River, where the Japanese took heavy losses from U.S. artillery and aircraft bombardment. Further west, Puller's 1st Battalion, 7th Marines trapped the Japanese 2nd Battalion, 4th Infantry in a wooded ravine. After calling for massed artillery fire into the ravine, Puller added the fire of his battalion's mortars to create, in Puller's words, a "machine for extermination". The trapped Japanese troops attempted several times to escape by climbing the opposite side of the ravine, only to be cut down in large numbers by massed Marine rifle and machine gun fire. Having received intelligence information that the Japanese were planning a large surprise offensive somewhere on Guadalcanal, Vandegrift ordered all the Marine units west of the Matanikau to disengage and return to the east side of the river, which was accomplished by the evening of 9 October.[51]

Dead Japanese soldiers lie in the wooded ravine after being killed by Puller's troops on 9 October.

The Marine offensive inflicted heavy casualties on the Japanese 4th Infantry Regiment, killing around 700 Japanese troops. During this operation, 65 Marines were killed.[52]

The same night that the U.S. Marine Matanikau operation ended on 9 October, Lieutenant General Harukichi Hyakutake—the Japanese 17th Army commander—landed on Guadalcanal to personally lead the Japanese forces in their planned large offensive scheduled for later in October. Hyakutake was immediately briefed on the loss of the Japanese positions on the east bank of the Matanikau and the annihilation of one of the 4th Infantry Regiment's battalions. Hyakutake communicated the news directly to the Army's General Staff in Tokyo where Lieutenant General Moritake Tanabe of the Operations Division noted in his diary that the loss of the Matanikau position was a "very bad omen" for the planned October offensive.[53]

The Japanese determined that the reestablishment of their forces on the east bank of the Matanikau would be prohibitive in terms of the number of troops required to accomplish it. Therefore, the Japanese devised a plan of attack for their scheduled offensive that sent many of their troops on a long and arduous journey to attack the U.S. Lunga perimeter from inland. The march—which began on 16 October—exhausted the Japanese troops involved to such an extent that it was later considered as one of the major factors in the decisive Japanese defeat in the subsequent Battle for Henderson Field from 23 to 26 October 1942. Thus, the failure of the Japanese to gain and hold a strong position on the Matanikau proved to have lasting strategic consequences in the battle for Guadalcanal, significantly contributing to the ultimate Allied victory in the campaign.[54]