Japan Never Knew Skip-Bombing Let B-25s Hit From 50 Feet With 99% Accuracy

Port Moresby, New Guinea, January fifteenth, nineteen forty-three. Captain William Benn's B-twenty-five Mitchell pulled up hard from seven thousand feet, his bombardier calling out the drop. Four five-hundred-pound bombs fell toward a Japanese transport steaming below. Benn watched them tumble, calculating wind, target speed, altitude. The mathematics seemed perfect. All four bombs missed by three hundred yards.
Benn's squadron had flown forty-two missions against Japanese shipping in the previous six months. They had scored exactly three direct hits. A seven percent success rate. Sometimes lower. The mathematics were brutal and consistent. Conventional level bombing from altitude could not reliably hit moving ships. Japanese convoy commanders knew this. Their confidence in evasive maneuvers and weather had been validated by every failed Allied bombing attempt across the Southwest Pacific.
What Japanese naval intelligence did not know, could not know from observing those failed high-altitude attacks, was that five hundred miles south, a fifty-two-year-old former Navy chief petty officer named Paul Irvin Gunn had spent six months perfecting a bombing technique that would render every assumption about bomber effectiveness obsolete. A technique so simple in concept, so devastating in execution, that it would turn medium bombers into precision weapons capable of hitting from fifty feet with accuracy rates seven times higher than conventional methods.
The Japanese had built their entire convoy defense doctrine on one fundamental truth: bombers attacking from altitude missed. Their mathematics were sound. Their observations were accurate. Their conclusion was fatal. Because Allied aircrew were no longer attacking from altitude.
Rabaul, December nineteen forty-two. Japanese naval staff officers reviewed Allied bomber effectiveness reports with satisfaction. American B-seventeen Flying Fortresses had attacked seventeen convoys in the previous four months. Hit rate: four point two percent. Australian Beaufort bombers had fared worse. Two point eight percent against shipping. Even the feared B-twenty-four Liberators managed only six percent accuracy on their best days.
Commander Masatake Okumura, staff officer for the Southeast Area Fleet, compiled the statistics in his daily reports. Of one hundred and forty-seven bombs dropped at Japanese shipping in November alone, six had struck targets. Four percent. The numbers told a consistent story. Level bombing from medium to high altitude could not reliably hit maneuvering vessels. Ships changed course randomly. Wind drift affected bomb trajectories. Altitude created time for evasive action. The mathematics favored the defender overwhelmingly.
Japanese doctrine reflected this reality. Convoy formations spread ships apart. Destroyers maintained anti-aircraft stations at maximum range. Captains trained crews in evasive patterns, zigzag courses, speed changes. The system worked. Convoys reached their destinations. Losses to air attack remained minimal, acceptable. Tokyo's planners authorized increasingly ambitious operations. The Southwest Pacific sea lanes remained open.
Imperial Navy training manuals dedicated three pages to defending against torpedo bombers. Twelve pages to coordinating fighter cover. Half a page to level bombing defense. The threat assessment seemed accurate. Torpedo attacks required aircraft to approach low and slow, vulnerable to every gun on the ship. Fighter sweeps could be countered with Zeros. But level bombers attacking from seven thousand feet or higher posed minimal danger. Let them drop their loads. Let them photograph the misses. The ships would continue.
What these reports did not capture, could not capture, was the frustration building among Allied aircrew. Men who trained for months, who risked their lives on eight-hour missions, who watched their bombs splash harmlessly into the ocean hundreds of yards from targets. The mathematics of conventional bombing were simple and devastating. A bomb dropped from seven thousand feet fell for approximately twenty seconds. A ship traveling at twelve knots moved four hundred feet in those twenty seconds. Wind could push the bomb two hundred feet off course. The bombardier had to predict where the ship would be, compensate for wind, account for altitude, temperature, bomb ballistics.