Ultimately, Operation K achieved none of its goals. No damage was inflicted on Pearl Harbor’s facilities, and the reconnaissance yielded extremely little intelligence due to the cloud cover.
The Second World War was a conflict defined by many strategic surprises. Even before the Japanese lightning attack on Pearl Harbor, the Nazis had subjected Europe to stunning blitzkrieg warfare that toppled France and the Low Countries and nearly conquered Britain.
From there, Hitler used similar tactics against his supposed ally, the Soviet Union. Meanwhile, in the months that followed Pearl Harbor, the Japanese conducted multiple dazzling surprise attacks across Asia, including against the Philippines and British-held Singapore.
But the Japanese planned for even more.
Indeed, Tokyo’s strategists understood that the United States’ tremendous advantage in industrial might would require Japan to keep it off-balance by conducting surprise attacks against US targets. To this end, Japan plotted to bomb the Panama Canal, thereby depriving the US Navy of its ability to quickly move its naval forces between the Atlantic and Pacific Oceans.
The Forgotten “Second Pearl Harbor”
Few know about Japan’s planned sequel to the Pearl Harbor attacks, though. Dubbed by the Imperial Japanese Navy (IJN) as “Operation K,” this daring raid against a Pearl Harbor that was still rebuilding from the original Japanese surprise attack largely failed to materialize. But Japan’s “Second Pearl Harbor,” had it occurred, would likely have been just as devastating for the Americans.
Unlike the carrier-based assault conducted by Japan on December 7, 1941, Operation K relied on long-range flying boats and submarine support, representing an ambitious attempt to extend Japanese reach across the vast Pacific Ocean.
Planning for Operation K began in the weeks following the Pearl Harbor attack, as Japanese naval command recognized the need for updated intelligence on American recovery operations. The IJN high command initially considered bombing targets on the US mainland, such as California and Texas, but prioritized reconnaissance and disruption at Pearl Harbor to hinder the US Navy’s repairs to its damaged fleet. The operation’s primary objectives were twofold: to gather visual intelligence on the status of American ships and facilities—notably the “Ten-Ten” dock (a 1,010-foot repair facility)—and to bomb key targets to slow salvage efforts.
Tokyo was hoping to buy more time for itself to consolidate the many gains it made in the Pacific following the successful Pearl Harbor strike before the Americans could fully rebuild their navy.
Operation K would have leveraged the capabilities of the Kawanishi H8K “Emily” Flying Boat, a four-plane engine seaplane renowned for its exceptional range (up to 4,400 miles) and ability to carry a payload of four 551-pound bombs.
Initially, Operation K’s plans called for five H8Ks, but due to availability issues, only two were deployed. To overcome the immense distances involved—over 3,000 miles roundtrip from the Marshall Islands—the aircraft would refuel at French Frigate Shoals, a remote atoll in the Northwestern Hawaiian Islands, using fuel supplied by IJN submarines, I-15, I-19, and I-26.
Submarine I-23 was tasked as a “lifeguard” and weather spotter south of Oahu, but was lost in rough seas sometime after February 14, 1942, complicating the operation. The raid was timed to coincide with a full moon for better visibility over Pearl Harbor, though execution depended on favorable weather for refueling and clear skies for bombing.
American codebreakers detected signs of the Japanese attack preparations, including refueling at the French Frigate Shoals. The American codebreakers issued warnings to their leadership.
But, as with pre-December 7 signals, these messages were largely ignored by superiors, underscoring persistent flaws in US readiness. Meanwhile, reconnaissance flights by submarine-launched floatplanes, such as one from the IJN I-19 submarine on February 23, provided preliminary data.
Why the Second Pearl Harbor Failed
The execution of Operation K commenced on March 4, 1942. The two H8Ks departed from Wotje Atoll in the Marshall Islands, each loaded with four bombs, and flew around 1,900 miles to the French Frigate Shoals for refueling. After topping off their tanks, they proceeded another 560 miles to Oahu. American radars on Kauai and Oahu detected the incoming aircraft, prompting the launch of Curtiss P-40 Warhawk fighters and Consolidated PBY Catalina patrols to search for presumed Japanese carriers.
Thick nimbus clouds over Pearl Harbor shielded the H8Ks from visual detection, allowing them to approach at 15,000 feet.
Using the Kaena Point lighthouse as a reference point, one of the H8Ks dropped its bombs from the north. Poor visibility caused these bombs to land on the slopes of Tantalus Peak, an extinct volcano north of Honolulu. The explosions created craters six-to-ten-feet deep, and 20-30 feet wide, shattering windows at nearby Roosevelt High School but causing no injuries or serious damage. Meanwhile, the second H8K is believed to have likely dropped its bombs in the ocean, as there were no additional impacts recorded.
The pair of H8Ks then retreated to the southwest. One of the H8Ks returned to Wotje, while the other, piloted by Lieutenant Hisao Hashizume, had sustained hull damage from taking off at the Shoals on its way to attack Pearl Harbor. As a result of this damage, he flew his H8K nonstop to Jaluit Atoll in the Marshall Islands, completing what was then the longest bombing mission in history—over 4,750 miles in nearly 36 hours.
Ultimately, Operation K achieved none of its goals. No damage was inflicted on Pearl Harbor’s facilities, and the reconnaissance yielded extremely little intelligence due to the cloud cover. There were no American casualties, and the raid’s only tangible effect was minor property damage far from the target. Factors contributing to the failure included adverse weather, the loss of I-23 for weather reporting, and a recent US Navy code change that left Japanese pilots without accurate forecasts.
What’s more, Operation K lacked fighter escorts, exposing the H8Ks to potential interception—although the same cloud cover that prevented the Japanese bombs from landing where they were meant to also protected the Japanese H8Ks from American defenders at Hawaii.
And once the operation was complete, the chance to repeat it was lost. Because of the failed attack, the Americans imposed entirely new security measures around the island that thwarted a planned follow-up reconnaissance mission in May 1942.
Therefore, Japan was denied critical intelligence on US carrier positions just ahead of the Battle of Midway—a decisive US victory that turned the tide in the Pacific. However inadvertently, Operation K contributed to Japan’s strategic defeat.
But the operation, while a failure, did highlight the IJN’s ambition and ingenuity in conducting complex, long-range missions. Its legacy lies not in the battlefield, but chiefly in the lessons it imparted. For Japan, the operation highlighted the perils of overextension; for the United States, it demonstrated the value of heightened vigilance. As the war progressed, these dynamics would shape the grueling campaigns that followed, ultimately leading to Allied victory.
About the Author: Brandon J. Weichert
Brandon J. Weichert, a Senior National Security Editor at The National Interest as well as a contributor at Popular Mechanics, who consults regularly with various government institutions and private organizations on geopolitical issues. Weichert’s writings have appeared in multiple publications, including the Washington Times, National Review, The American Spectator, MSN, the Asia Times, and countless others. His books include Winning Space: How America Remains a Superpower, Biohacked: China’s Race to Control Life, and The Shadow War: Iran’s Quest for Supremacy. His newest book, A Disaster of Our Own Making: How the West Lost Ukraine is available for purchase wherever books are sold. He can be followed via Twitter @WeTheBrandon.
Image: Wikimedia Commons.
