On the morning of August 7, 1942, the first day of the American landings on Guadalcanal, a man named Paul Mason sat on a hilltop at the southern end of Japanese-held Bougainville Island and watched a formation pass overhead. He had a radio, a vantage point over Buin and the Shortland Islands, and no way off the island. He sent the message the American commanders had been waiting for: twenty-four bombers were on their way. For the entire month of August 1942, there was no radar on Guadalcanal at all.
The Marines had managed without it. Instead, they had Mason, a civilian plantation manager, and another man at the opposite end of the same island chain. Together, they provided the only early warning the defenders of Henderson Field would get. The air raid warning system depended on wireless messages of six or seven words, sent by two men who were not members of any armed force.
The warning from Bougainville gave Guadalcanal forty to forty-five minutes of lead time, sometimes more. That interval was everything. A Grumman Wildcat climbing out of Henderson Field gained about five hundred feet per minute. The bombers it had to intercept crossed the coast at twenty-five thousand feet or higher.
A fighter taking off from the ground needed nearly forty minutes to reach an altitude above formations that had already reached theirs. The warning time was not a convenience; it was the entire margin of survival. At the northern end of Bougainville, roughly 350 miles from Mason, a former district officer named Jack Read watched the same air traffic from a hideout in Bora Bora, overlooking the Buka Passage and the channels running southeast through the waters the Americans called the Slot. Every Japanese aircraft coming from Rabaul had to cross that region.
Read’s reports reached Guadalcanal about thirty minutes before Mason’s, and an hour or more before the southern stations, because he was closer to the point where formations assembled with their fighter escorts. More importantly, over Bora Bora the planes were still low, still climbing, and still in formation, so Read could count them and identify them. Not just aircraft approaching, but nine bombers and eighteen fighters, the kind of information a fighter director needed before deciding how much force to commit and how much to hold back. Read wrote up the entire operation later, in a 148-page report divided into eleven parts and twelve appendices, signed on July 1974, thirty-one years after he left the island.
On Guadalcanal, the warnings arrived at a one-story wooden building the Japanese had built before the Marines took the airstrip, called the Pagoda by the Americans. It sat on a rise about two hundred yards northwest of the runway and served as both observation tower and air operations center. Colonel Albert Cooley of Marine Air Group 14 summarized the choice of location without affection: you could see it from forty miles away. The first alarm was a captured Japanese whistle, which proved useless.
In so small an area, the whistle sounded at the same moment the bombs arrived. So Seabees from the 1st Construction Battalion rigged a flagpole above the Pagoda instead. A white flag meant bombers were on the way. A black flag meant two minutes or less, or that they were overhead.
No flag meant nothing had been spotted yet, which on Guadalcanal usually meant nothing had been spotted on two hills three hundred miles away, rather than in the sky overhead. Brigadier General Louis Woods, who ran the Cactus Air Force through its worst weeks, considered putting the air operations center on the most prominent hill on the island a bad decision. The Japanese eventually leveled the building. The Seabees who took on the warning post duty were not specialists.
The 1st Construction Battalion arrived on the beach on August 15 with five officers and 118 enlisted sailors. Most were recent graduates of technical schools, and the unit had been sent in such haste that it arrived with four main tool boxes and almost nothing else. The runway they were meant to support was worse than its reputation. Japanese engineers had started building the field from both ends and left a gap in the middle about sixty yards wide.
The Marines’ first task was to move 5,000 cubic yards of earth using hand tools and captured dump trucks, smooth it with a captured road roller, and surface it by dragging a steel beam. The entire field sat in a basin, so rainwater collected and stayed. Vandegrift declared the field ready for fighters and dive bombers on August 12. There were no taxiways, no revetments, and no drainage system.
Perforated Marston matting covered a thousand feet of runway for traction on the soft ground, while the rest was packed earth that turned to black mud within an hour of rain and crumbled under the sun into dust fine enough to destroy any engine. Colonel Fiske Marshall, who arrived in September to take command of Marine Air Group 25, said the place looked like a drawing from Doré’s depictions of hell. Captain Dale Brannon of VMF-67 took off P-400s from that surface. His method was to set the wings to half flap for extra lift, press hard on the brakes, run the engine up to maximum power, then let the aircraft pull itself through the mud while the brakes stayed locked.
Then he released the brakes and began to steer. In the first weeks, the runway cost nearly as many aircraft as the Japanese did. There was a secondary strip nearby, officially called Fighter 1, universally known as the Cow Pasture because it had no metal matting, just a strip of mown grass. The men taking off from that ground were beginners.
Major Richard Mangrum reviewed the flight records of his replacement pilots before the squadron sailed and found none with more than two hundred hours of flying time. The Japanese aircrews coming down from Rabaul averaged around eight hundred. Forty minutes bought a particular tactic, developed by Major John L. Smith of VMF-223.
The Wildcat could not match the A6M Zero in a straight fight, and Smith did not try. He trained his pilots to climb ahead of the incoming formation and to the side, then turn hard onto the opposite heading five thousand feet above the bombers, roll inverted, and dive through them. This kept the Wildcats out of the Betty bombers’ defensive guns and allowed direct hits on fuel tanks, with no effective way for the bombers to fight back. After the first pass, the fighters turned left in a climb and watched.
If the escorts had not arrived, they repeated the attack. If the escorts had arrived, they dove away toward the antiaircraft guns over the airfield or hid in clouds, because the objective was the bombers and tangling with a Zero meant certain death. Every part of that depended on being five thousand feet above the formation before it got there. It was not a method anyone could execute from scratch, which made October 2, 1942, an instructive day.
The Marine Air Group 23 war diary logged an air raid warning at 12:30 that day, as radar reported a group of small fast aircraft approaching Henderson Field. Fourteen Wildcats of Smith’s VF-511 unit took off, along with eleven of VF-224 and seven Dauntless dive bombers. Half an hour later, about thirty Zeros were engaged over the airfield. The Japanese had sent fighters instead of bombers, meaning a faster approach and a smaller radar return, and thirty minutes was not the same as forty.
The Wildcats were still climbing when the Zeros fell on them. Four Zeros were shot down. Six American fighters were lost, and only two of their six pilots survived. One of the men shot down that afternoon was John Smith himself.
He came out of a cloud to find three Zeros ahead of him, destroyed one, took cannon fire from the other two, lost his engine, and put his aircraft down in kunai grass four miles east of the airfield. Marion Carl had radioed a warning to him using a set salvaged from a wrecked dive bomber. The man who had figured out how to shoot down Betties from above spent that engagement underneath everyone. The warning time was the variable that mattered.
Not the warning itself. The SCR-270-B radar that arrived on September 2 could pick up high formations at 150 miles, which in theory made the men on Bougainville unnecessary. But in practice, the radar gave a bearing, a distance, and an approximate altitude. It could not tell the fighter director whether the target was a full bomber strike with an escort of equal size or a single reconnaissance plane.
That difference decided whether the Cactus Air Force launched everything it had or held most of it in reserve. When twenty-five Betties and fifteen Zeros attacked on September 12, the airfield launched twenty Wildcats based on both sources at once, the radar and coastwatcher Donald Kennedy in New Georgia. Neither alone would have sufficed. Sixteen days later, with both reporting again, thirty-five fighters went up against an equivalent Japanese force of bombers and escorts, and the escort lost eight of its number without protecting the formation it had come to defend.
Between late August and mid-November, the Japanese lost nearly 96 fighters, 92 Betties, and 75 other aircraft over that stretch of water. The Cactus Air Force lost 118 aircraft shot down and wrote off another 30 in accidents, with 84 pilots killed from all causes. Here is the part that complicates the whole account. The raids were predictable without any warning at all.
Rabaul lay roughly 560 miles from Guadalcanal. A Betty making that round trip before dark had no fuel for deviations and no daylight to wait. So formations arrived on most days between 11:30 a. m.
and 2:30 p. m. , a schedule so consistent the Marines called it Tojo Time and set their watches by it. Any commander with a map and the G4M’s range figures could tell his pilots roughly when to be in the air.
What the clock could not tell them was the numbers, the types, or whether this was the morning the Japanese decided to send everything they had. That is what the two men on Bougainville actually provided. By late October 1942, Japanese command had taken a firm position on the coastwatchers: they had to be eliminated. It was known that two men were hiding in the jungle at opposite ends of Bougainville.
A hundred troops moved into the Buin area to hunt Mason, bringing tracker dogs. Mason’s response was to radio Guadalcanal and ask for the dogs to be bombed. A Catalina came and bombed Buin. The dogs were in their cages at the time.
Others paid a far higher price for the network than the two men on the hills. In January 1943, the Japanese gathered the local people at Kieta and executed the headman Baros in front of them, after he had sheltered Allied personnel in his village, refused to disclose where Mason was hiding, and refused again when given a final chance to answer. Mason had spent seventeen years on Bougainville by then. He had taken over the Aenos plantation in 1925, succeeding a manager his own workers had killed.
He was skilled at repairing radios. Read had arrived in November 1941 as an assistant district officer, and when the civil administration closed in February 1942, he was the last government man left on the island. Neither had been trained for any of this. Both were given ranks in the Royal Australian Navy Volunteer Reserve on paper, on the theory that a naval rank might protect them if captured alive, which no one involved believed for a moment.
What ended the Bougainville stations in the end was not aircraft. It was infantry and dogs, enough men on the ground to make the hills untenable. In July 1943, about seventeen months after the campaign began, an American submarine evacuated Mason and Read. Mason returned in 1944 to run guerrilla operations against the same garrison that had spent a year searching for him.
He died in Brisbane in 1972. The airfield had been named for Major Lofton Henderson, a Marine dive bomber pilot killed at Midway. Major Kenneth Weir, the division air officer, pushed the name through with a reason having nothing to do with remembrance. If he had not, the field would have been named for some old men with big bellies behind desks in Washington.
The Marines kept the airfield. The two men who made keeping it possible spent the campaign three hundred miles up the chain on two hilltops, watching and sending sentences like the one Jack Read broadcast one August morning: forty-five dive bombers coming from the southeast.