The transports were guarded by 13 warships commanded by Japanese Rear Admiral Raizo Tanaka. He planned to land the troops on Guadalcanal on 24 August. To cover the landings and retake Henderson Field from Allied forces, Yamamoto directed Chuichi Nagumo to meet with a carrier force from Truk on 21 August and head towards the southern Solomon Islands. Nagumo's force included three carriers and 30 other warships.
Three U.S. carrier task forces under Fletcher approached Guadalcanal to attack the Japanese. On 24 and 25 August, the two carrier forces fought the Battle of the Eastern Solomons, which resulted in both fleets pulling back from the area after taking some damage. Japan lost one light aircraft carrier. Tanaka's convoy, after getting heavy damage during the battle from an air attack by aircraft from Henderson Field, including the sinking of one of the transports, changed direction to the Shortland Islands in the northern Solomons. This was done to transfer the troops to destroyers for delivery to Guadalcanal.
Throughout August, small numbers of U.S. aircraft and their crews continued to arrive at Guadalcanal. By the end of August, 64 aircraft of various types were stationed at Henderson Field. Air battles between the Allied aircraft at Henderson and Japanese bombers and fighters from Rabaul continued almost daily. Between 26 August and 5 September, the U.S. lost about 15 aircraft while the Japanese lost approximately 19 aircraft. More than half of the downed U.S. aircrews were rescued while most of the Japanese aircrews were never recovered. The eight-hour round trip flight from Rabaul to Guadalcanal, about total, made it hard for the Japanese to attack Henderson Field.
Australians on Bougainville and New Georgia islands were often able to warn of Japanese air strikes, allowing the U.S. fighters time to take off and attack the Japanese bombers and fighters as they approached the island.
Between 21 August and 3 September, three Marine battalions, including the 1st Raider Battalion, under Merritt A. Edson (Edson's Raiders), and the 1st Parachute Battalion from Tulagi and Gavutu went to Guadalcanal. These units added about 1,500 troops to the original 11,000 men defending Henderson Field. The 1st Parachute Battalion, which had many dead and wounded in the Battle of Tulagi and Gavutu-Tanambogo in August, was placed under Edson's command.
The other relocated battalion, the 1st Battalion, 5th Marine Regiment (1/5), was landed west of the Matanikau near Kokumbuna village on 27 August. They had the mission of attacking Japanese units in the area. They faced hot sun, and strong Japanese defenses. The next morning, the Marines found that the Japanese defenders had departed during the night, so the Marines returned to the Lunga perimeter by boat. Losses in this action were 20 Japanese and 3 Marines killed.
Small Allied naval convoys arrived at Guadalcanal on 23 August 29 August, 1 September, and 8 September. They provided the Marines at Lunga with more food, ammunition, aircraft fuel, and aircraft technicians. The 1 September convoy also brought 392 construction engineers to work on Henderson Field.
By 23 August, Kawaguchi's 35th Infantry Brigade reached Truk and was loaded onto slow transport ships for the rest of the trip to Guadalcanal. The damage done to Tanaka's convoy during the Battle of the Eastern Solomons made the Japanese decide not to deliver more troops to Guadalcanal by slow transport. Instead, ships carrying Kawaguchi's soldiers were sent to Rabaul.
From there, the Japanese planned to deliver Kawaguchi's men to Guadalcanal by destroyers. The Japanese destroyers were usually able to make round trips down (New Georgia Sound) to Guadalcanal and back in a single night throughout the campaign, minimizing their risk of Allied air attack.
The runs became known as the "Tokyo Express" to Allied Forces by the Japanese.
Delivering the troops like this made it hard to bring heavy equipment and supplies, such as heavy artillery, vehicles, and much food and ammunition to Guadalcanal. In addition, this activity used destroyers the IJN needed for commerce defense. The Allied naval commanders did not fight Japanese naval forces at night. However, any Japanese ship remaining within range of the aircraft at Henderson Field during the daylight hours, about , was in great danger from air attack. Thissituation existed for the next several months of the battle.
Between 29 August and 4 September, Japanese light cruisers, destroyers, and patrol boats were able to land almost 5,000 troops at Taivu Point, including most of the 35th Infantry Brigade, much of the Aoba (4th) Regiment, and the rest of Ichiki's regiment. General Kawaguchi, who landed at Taivu Point on 31 August Express run, was placed in command of all Japanese forces on Guadalcanal. A barge convoy took another 1,000 soldiers of Kawaguchi's brigade, under the command of Colonel Akinosuke Oka, to Kamimbo, west of the Lunga perimeter.
On 7 September, Kawaguchi issued his attack plan to destroy enemy in the Guadalcanal Island airfield. Kawaguchi's attack plan called for his forces to do a surprise night attack. Oka's forces would attack from the west while Ichiki's Second Echelon would attack from the east. The main attack would be by Kawaguchi's group of 3,000 men in three battalions, from the south. By 7 September, most of Kawaguchi's troops began marching towards Lunga Point along the coastline. About 250 Japanese troops remained behind to guard the brigade's supply base at Taivu.
Meanwhile, scouts brought reports to the U.S. Marines of Japanese troops at Taivu near the village of Tasimboko. Edson planned a raid on the Japanese troops at Taivu. On 8 September, after being dropped-off near Taivu by boat, Edson's men captured Tasimboko as the Japanese retreated into the jungle.
In Tasimboko, Edson's troops discovered Kawaguchi's main supply depot, including large stockpiles of food, ammunition, medical supplies, and a powerful shortwave radio. After destroying everything, except some papers, the Marines returned to the Lunga perimeter. The captured documents informed the Marines that at least 3,000 Japanese troops were on the island and planning an attack.
Edson, along with Colonel Gerald C. Thomas, Vandegrift's operations officer, thought that the Japanese attack would come at a narrow, grassy, -long, coral ridge south of Henderson Field. The ridge, called Lunga Ridge, had a good approach to the airfield and it was undefended. On 11 September, the 840 men of Edson's battalion were sent onto and around the ridge.
On the night of 12 September, Kawaguchi's 1st Battalion attacked the Raiders between the Lunga River and ridge. One Marine company had to fall back to the ridge before the Japanese stopped their attack for the night. The next night Kawaguchi had to battle Edson's 830 Raiders with 3,000 troops of his brigade and artillery. The Japanese attack began just after nightfall with Kawaguchi's 1st battalion attacking Edson's right side to the west of the ridge. After breaking through the Marine defences, the attack was eventually stopped by Marine units guarding the northern part of the ridge.
Two companies from Kawaguchi's 2nd Battalion moved up the southern edge of the ridge and pushed Edson's troops back to Hill 123 on the center part of the ridge. Throughout the night the Marines fought against Japanese attacks, some of which resulted in hand-to-hand fighting. The Marines also had artillery. Japanese groups that got past the ridge to the edge of the airfield were also sent back.
Attacks by the Kuma battalion and Oka's unit at other places were also stopped. On 14 September Kawaguchi led the survivors on a five-day march west to the Matanikau Valley to join with Oka's unit. In total Kawaguchi's forces lost about 850 killed and the Marines 104.