Clear communications is a vital aspect of victory for any military and history is replete with examples of communications screw-ups causing lost battles and disastrous casualties. At Battle of Cape Esperance during the Guadalcanal Campaign during World War II, a misunderstood radio message resulted in the U.S. Navy winning a significant victory against the Japanese Navy after its humiliating defeat at the Battle of Savo Island where the U.S. lost four heavy cruisers and more than a 1,000 sailors on the night of August 8-9, 1942.

With the U.S. invasion of the island of Guadalcanal in early August 1942, both the U.S. and Japanese Navies found themselves at relative parity to each other.  In June, the U.S. Navy had sunk four of Japan’s six fleet carriers losing the USS Yorktown in the exchange. This shift in the balance of naval power allowed the U.S. to go over to the offensive and make its landing on the island to prevent an airfield being built there interdicting U.S. supply lines to Australia.  The Japanese for their part were just as determined to hold it.

While the initial landings were a complete success, seeing the Japanese garrison driven off into the jungle, losses to fighter planes on the two U.S. carriers covering the landings cause their withdrawal out of range of Japanese planes flying from bases like Rabaul at the northwestern end of the Solomon islands chain.  The U.S. held the airfield, renamed Henderson Field, and were able to provide their own air cover, while the Japanese found Guadacanal was at the limits of the range of most of their aircraft except for twin-engine bombers. Their single-engine fighters and dive bombers could reach the island but could only loiter over the area for about 15 minutes before having to turn back. The result was that the Japanese could exert naval control of the waters around Guadalcanal at night, but would have to be at least 200 miles from the island by daybreak or risk attack by air from Henderson field.  The U.S. could land reinforcements during the day but would have to be well away from the island after dark when Japanese battleships, cruisers, and destroyers could sink their transports.

For both sides, this meant desperate attempts to resupply and build up their forces on the island, with whatever they could muster.  The Japanese were unable to use their slow-moving transports because they could not be clear of American air attacks by dawn so they employed destroyers and other fast warships in making supply runs. The U.S. could send transports into those waters but would need to screen them with warships and air cover from Henderson field in order for them to quickly unload and get clear themselves