Col Kiyono Ichiki, a battle-seasoned Japanese Army veteran, led his force in an impetuous and ill-fated attack on strong Marine positions in the Battle of the Tenaru on the night of 20–21 August.
Almost as Turner’s transports sailed away, the Japanese began a pattern of harassing air attacks on the beachhead. Sometimes the raids came during the day, but the 3d Defense Battalion’s 90mm antiaircraft guns forced the bombers to fly too high for effective bombing. The erratic pattern of bombs, however, meant that no place was safe near the airfield, the preferred target, and no place could claim it was bomb-free. The most disturbing aspect of Japanese air attacks soon became the nightly harassment by Japanese aircraft which singly, it seemed, roamed over the perimeter, dropping bombs and flares indiscriminately. The nightly visitors, whose planes’ engines were soon well known sounds, won the singular title “Washing Machine Charlie,” at first, and later, “Louie the Louse,” when their presence heralded Japanese shore bombardment. Technically, “Charlie” was a twin-engine night bomber from Rabaul. “Louie” was a cruiser float plane that signalled to the bombardment ships. But the harassed Marines used the names interchangeably.
Even though most of the division’s heavy engineering equipment had disappeared with the Navy’s transports, the resourceful Marines soon completed the airfield’s runway with captured Japanese gear. On 12 August Admiral McCain’s aide piloted in a PBY-5 Catalina flying boat and bumped to a halt on what was now officially Henderson Field, named for a Marine pilot, Major Lofton R. Henderson, lost at Midway. The Navy officer pronounced the airfield fit for fighter use and took off with a load of wounded Marines, the first of 2,879 to be evacuated. Henderson Field was the centerpiece of Vandegrift’s strategy; he would hold it at all costs.
Although it was only 2,000 feet long and lacked a taxiway and adequate drainage, the tiny airstrip, often riddled with potholes and rendered unusable because of frequent, torrential downpours, was essential to the success of the landing force. With it operational, supplies could be flown in and wounded flown out. At least in the Marines’ minds, Navy ships ceased to be the only lifeline for the defenders.
While Vandegrift’s Marines dug in east and west of Henderson Field, Japanese headquarters in Rabaul planned what it considered an effective response to the American offensive. Misled by intelligence estimates that the Marines numbered perhaps 2,000 men, Japanese staff officers believed that a modest force quickly sent could overwhelm the invaders.
On 12 August, CinCPac determined that a sizable Japanese force was massing at Truk to steam to the Solomons and attempt to eject the Americans. Ominously, the group included the heavy carriers Shokaku and Zuikaku and the light carrier Ryujo. Despite the painful losses at Savo Island, the only significant increases to American naval forces in the Solomons was the assignment of a new battleship, the South Dakota (BB 57).
Of his watercolor painting “Instructions to a Patrol,” Capt Donald L. Dickson said that three men have volunteered to locate a Japanese bivouac. The one in the center is a clean-cut corporal with the bearing of a high-school athlete. The man on the right is “rough and ready.” To the one at left, it’s just another job; he may do it heroically, but it’s just another job.
Captain Donald L. Dickson, USMCR
Imperial General Headquarters in Tokyo had ordered Lieutenant General Haruyoshi Hyakutake’s Seventeenth Army to attack the Marine perimeter. For his assault force, Hyakutake chose the 35th Infantry Brigade (Reinforced), commanded by Major General Kiyotake Kawaguchi. At the time, Kawaguchi’s main force was in the Palaus. Hyakutake selected a crack infantry regiment—the 28th—commanded by Colonel Kiyono Ichiki to land first. Alerted for its mission while it was at Guam, the Ichiki Detachment assault echelon, one battalion of 900 men, was transported to the Solomons on the only shipping available, six destroyers. As a result the troops carried just small amounts of ordnance and supplies. A follow-on echelon of 1,200 of Ichiki’s troops was to join the assault battalion on Guadalcanal.