The marines would later be reinforced adequately on 18 September, and were well prepared with an even larger numerical superiority, more heavy weapons and tanks to meet the next Japanese offensive.

[6] By 9 August, 10,900 troops from Major General Alexander Vandegrift's 1st Marine Division were on Guadalcanal, occupying a loose perimeter around the Lunga Point area.

[9] Underestimating the strength of Allied forces on Guadalcanal, Ichiki's First Element conducted a nighttime frontal assault on Marine positions at Alligator Creek on the east side of the Lunga perimeter in the early morning hours of 21 August.

The Japanese destroyers were usually able to make the round trip down "The Slot" to Guadalcanal and back in a single night, minimizing their exposure to Allied air attack.

These high-speed destroyer runs to Guadalcanal, which occurred throughout the campaign, were later called the "Tokyo Express" by Allied forces and "Rat Transportation" by the Japanese.

However, any Japanese ship remaining within the 200 mi (320 km) range of the aircraft at Henderson Field in daylight was in great danger from air attacks.

At 18:05 that day, 11 U.S. dive bombers from VMSB-232, under the command of Lt. Col. Richard Mangrum,[14] flew from Henderson Field and located and attacked DD20 about 70 mi (110 km) north of Guadalcanal, sinking Asagiri and heavily damaging Yugiri and Shirakumo.

Therefore, a convoy carrying 1,100 of Kawaguchi's troops and heavy equipment in 61 barges, mainly from the 2nd Battalion, 124th Infantry Regiment under the command of Colonel Akinosuka Oka, departed the northern coast of Santa Isabel Island on 2 September.

Kawaguchi's plan called for his forces to split into three, approach the Lunga perimeter inland, and launch a surprise night attack.

Supported by aircraft from Henderson Field and gunfire from the destroyer transports, Edson's men advanced towards Tasimboko village but were slowed by Japanese resistance.

The Japanese defenders, believing a major landing was underway after observing the concurrent approach of an Allied supply ship convoy heading towards Lunga Point, retreated into the jungle, leaving behind 27 dead.

Finally, Thomas convinced Vandegrift that the ridge was a good location for Edson's Raiders to "rest" from their actions of the preceding month.

[30] Kawaguchi's Center Body of troops was planning to attack the Lunga perimeter at the ridge, which they called "the centipede" (mukade gata) because of its shape.

Lack of good maps, at least one faulty compass, and thick, almost impenetrable jungle caused the Japanese columns to proceed slowly and zigzag, costing a lot of time.

Kawaguchi, who was having trouble locating where he was in relation to the Marine lines as well as coordinating his troops' attacks, later complained, "Due to the devilish jungle, the brigade was scattered all over and was completely beyond my control.

In addition, a battery of four 105 mm howitzers from the 3rd Battalion, 11th Marine Regiment under Lieutenant Colonel James J. Keating moved to a location from where it could provide direct fire onto the ridge, and a forward artillery observer was placed with Edson's front line units.

[37] Late in the afternoon, Edson stepped onto a grenade box and addressed his exhausted troops, saying, You men have done a great job, and I have just one more thing to ask of you.

"[42] The Japanese hit Edson's left flank just after the Parachutists took position but were again stopped by Marine rifle, machine-gun, mortar, and grenade fire.

But with Tamura's battalion shattered after losing three-quarters of its officers and men, and with heavy casualties to his other attacking units as well, Kawaguchi's assault on the ridge had effectively ended.

[46] As the battle on the ridge took place, Kawaguchi's Kuma and Oka units also attacked the Marine defenses on the east and west sides of the Lunga perimeter.

After daybreak, the Marines, believing that the rest of Mizuno'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, and while some of the tanks' crewmen were able to escape the flames, several of them were bayoneted and killed by the Japanese.

At about 04:00 on 14 September, two Japanese companies attacked positions held by the 3rd Battalion, 5th Marine Regiment (3/5) near the coast and were thrown back with heavy losses.

Another Japanese company captured a small ridge somewhat inland but was then pinned down by Marine artillery fire throughout the day and took heavy losses before withdrawing on the evening of 14 September.

As the march progressed, the exhausted and hungry soldiers, who had eaten their last rations on the morning before their withdrawal, began to discard their heavy equipment and then their rifles.

Nevertheless, after a torrent of tenacious assaults, Kawaguchi's men managed to breach the marine line and reach the outskirts of Henderson field.

Smith mentions that if even one additional battalion struck the ridge during the main assault, the pendulum could've swung in the Japanese's favor, with how close the fight was.

[9] The severity of the fighting and the losses incurred led to Vandegrift renewing requests for reinforcement, the convoy that was dispatched to supplement the marines turned back after the USS Wasp, an escorting carrier, was sunk by Japanese submarine action, along with a destroyer sunk and a Battleship heavily damaged, but the attempt was renewed later and the marines were reinforced by 18 September.

In an emergency session, the top Japanese army and navy command staffs concluded that "Guadalcanal might develop into the decisive battle of the war."

Hyakutake realized that in order to send sufficient troops and materiel to defeat the Allied forces on Guadalcanal, he could no longer support the major Japanese offensive on the Kokoda Track in New Guinea.

Vandegrift later stated that Kawaguchi's assault on the ridge in September was the only time during the entire campaign he had doubts about the outcome and that had it succeeded, "we would have been in a pretty bad condition.