After Henderson Field on Guadalcanal became operational, Japanese naval surface forces avoided the island during the day, but after some sharp and expensive night engagements off the island the Allies ceded night control of those waters to the Japanese. This allowed the Japanese to bring in reinforcements and supplies to their troops via what was dubbed the “Tokyo Express.”
Groups of fast Japanese ships would form near the Shortland Islands and would time their voyages to put them within bomber range of Guadalcanal just before dusk, run in, offload, and try to be back out of range by dawn. Information supplied by the coastwatchers, patrolling aircraft, and signal intelligence made those runs harder and less effective.
There was enormous variation between the experiences of the several watchers. District officer and coastwatcher Martin Clemens hurried back to the islands from leave in Australia when he heard about Pearl Harbor. At his insistence, he was assigned as an assistant to Dick Horton, who was then stationed on Guadalcanal. They moved back into the hills when they got the first report of the Japanese occupying the nearby island of Tulagi
Another stay behind was District Officer Donald Kennedy, who set up shop at Segi Point near the south end of New Georgia Island. He had a talent for dealing with the natives and for keeping the primitive electronics of the day working. By the time the advancing Allies reached him, he had gained a reputation as a formidable warrior.
Kennedy had recruited a “half-caste” native medical practitioner named Geoffrey Kuper, the son of a German planter and his native wife. Initially Kuper worked on getting stranded contract workers back to their home islands. On his own he rescued an aviator from theaircraft carrier USS Enterprise,who was shot down during a strike on Tulagi.
His rescue work was so effective that Kennedy set him up with his own coastwatcher station. He established it on Tataba just in time for the big air battles as the Japanese attempted to knock out Henderson Field; over the next few weeks Kuper and his scouts rescued dozens of downed flyers.
Signal intelligence was of paramount importance in the vast spaces of the Pacific, but the coastwatchers were invaluable in the narrow seas around the Solomons. The Allies actually began to benefit from the coastwatchers before the invasion when Paul Mason reported Japanese ships heading for the Battle of the Coral Sea.
Japanese air attacks against Guadalcanal launched from fields around Rabaul would pass over Bougainville. Once the battle for Guadalcanal began, both Mason and Read began reporting on the Japanese bombers as they headed for that island. The Allied commanders showed that they understood the value of the coastwatchers by briefing their headquarters about planned operations so that the watchers could be placed to best advantage.
After the Marines landed on Guadalcanal, the coastwatchers at large on the island came into their perimeter and set up a Solomon Islands headquarters. Feldt sent his deputy, Lt. Cmdr. Hugh Mackenzie, to take charge of that headquarters.
But Japanese naval thrusts were getting past Bougainville and New Georgia unobserved, thus showing the need for more watchers, so teams slipped into the jungles of Vella Lavella and Choiseul. Nick Waddell, who had been stationed on Choiseul previously, and Carden Seton, a former planter in the islands, were chosen for that station, while Henry Josselyn and John Keenan established the post on Vella Lavella. There was too much Japanese air activity in the area to fly them, so the teams went in by submarine.
Josselyn and Keenan made it across the coral reef that ringed the island in spite of a leaking rubber raft and not being able to find a gap in the reef. Without making any contact with the natives, they made their way to the deserted Mundi Mundi plantation house and set up shop in a camouflaged lean-to on a nearby hill, only to have their teleradeo break down almost immediately. Fortunately, friendly natives happened by so they were able to arrange for relays of canoes to take Josselyn 150 miles to Kennedy’s post.
After requesting parts for the machine only to have them destroyed when dropped from an airplane, Kennedy gave Josselyn his own radio. He was sure he would be able to fix one he had pulled from a crashed Japanese plane. Eventually the natives returned Joselyn to Mundi Mundi, where the station became operational.
Waddell and Seaton had an exciting time getting to their station on Choiseul. As the submarine was moving into position to launch their rubber rafts, word came that the Tokyo Express, a fresh Japanes destroyer convoy, was running and the submarine was to take station to intercept the enemy. The submarine found the convoy, launched a torpedo attack, and was depth charged in return.
Eventually the submarine returned to the section of the coast where the men were to land. They fought their way across the fringing reef and onto shore, barely getting their supplies and the rafts under cover before daylight. The station was soon operational.
When the Japanese established a seaplane base on Santa Isabel Island, Guy Cooper and a team of native scouts were deployed to keep an eye on it. Scouts offered the Japanese at the base fish and other food and soon had the run of the whole facility. A second post was also established and manned on that island by J.A. Corrigan.
All of these posts were operational by March 1943, which put Japanese ship and air movements through the islands under almost constant surveillance. This allowed the Allies to mount attacks that seriously interfered with Japanese attempts to build up bases in the islands. When Japanese aircraft flew south from Rabaul, watchers on Bougainville could give Guadalcanal and ships in nearby waters about two hours’ warning of an impending raid.
Fortunately, even without coastwatcher warnings the time of day when Japanese aerial attacks on Guadalcanal could be expected was quite predictable. The range to their targets was such that there was no fuel or time to do anything but fly the most direct route. In order to return to base before dark, the raid had to reach Guadalcanal about noon.
These distances were a long way for a damaged aircraft to fly, and a great many Japanese aircraft went down somewhere along the “Slot,”—the strait between New Georgia and Santa Isabel. If the aircrew made it safely to the surface, there was a good chance they would end up in the hands of the natives. The lucky ones were turned over to a watcher and sent back to Guadalcanal, where they were a useful source of information.
To give them more flexibility in timing their raids and to give their flyers a better chance of making it back, the Japanese began building airfields in the northern Solomons. They expanded the one the Australians had begun on Buna and began building another one near Mason’s station on Matabita Hill. This forced him farther back from the coast, which interfered with some of his observations. It was also the beginning of serious Japanese efforts to capture him and Reed.
This was one of the few times the Japanese made determined efforts to eliminate coastwatchers; apparently they finally grasped the damage that Reed and Mason were doing. It was easy to see the relationship between coded messages from the interior of Bougainville soon after Japanese air raids passed overhead and the flights being intercepted as they neared Guadalcanal.
Reed’s and Mason’s positions were also more tenuous than those of most watchers. There were thousands of Japanese on Bougainville, and as the campaign progressed their bases were multiplying. This made Japanese claims plausible that the day of the white man in the islands was over and most of the villages were under Japanese guns.
Whatever motivated them, a number of villagers began cooperating with the Japanese, providing them with porters for their patrols and, more importantly, information on the watchers’ locations. Reed and Mason retaliated by calling for air attacks on the collaborators’ villages.
A watcher on Guadalcanal named McKenzie reinforced Reed with several more watchers, replacing the Australian commandos that had been in the bush since the beginning of the campaign. Reed used the new arrivals to reestablish his network, but by then the growing strength of the Japanese and the disaffection of the natives made it impossible to continue.
One by one the new posts were overrun and forced off the air. Several watchers and scouts were killed in the attacks and a number captured. Some were executed on the spot and others taken prisoner to be executed later.
The decision was made to evacuate the remaining watchers and scouts. They were no longer producing useful information, and other posts were now in position to substitute for them.
Injured flyers and the remaining missionaries and Chinese merchants were also evacuated by submarine. The decision was a sound one, although there were more casualties on the way to the coast.