On October 4, 1942 Lt. Commander Kenji Mitsui was landed by a destroyer near Lunga on Guadalcanal. From atop a Mount Austen, the highest point in that area on Guadalcanal, he lived in a camouflaged foxhole and reported on American movements, progress of battles and aerial activity using a radio to transmit messages to Rabaul. Clearly visible from his lookout position was Henderson Field, the American perimeter, Lunga Point anchorage and Tulagi in the distance.
Ewan Stevenson adds:
"The closest thing the Japs had to the coastwatchers was various ‘outposts’ with radios. They were dotted around like at Astrolabe on Malaita, Marau on Guadalcanal, Cape Hunter, Koilutumaria also isolated outposts on Rendova, and Vella Lavella, etc. The Allied CW used to watch these outposts as well! A crashed Catalina crew accidentally stumbled into a Jap CW post on Vella and I think some of the crew killed in the fray."
References
Sydney Morning Herald "Secret Battle of Guadalcanal" by D. Jenkins May 7, 1974
War by Stealth by Alan Powell
Thanks to John Innes, Stan Jersey, Ewan Stevenson and Peter Flahavin and Justin Taylan for additional information