During a little-known raid, Japan's newest four-engine
flying boat was put to a challenging test:
a flight of more than 3,000 miles to attack Hawaii.

On March 4, 1942, the bright moonlight over the Oahu sky was suddenly obscured by a light tropical rain. The Hawaiian Islands were blacked out except for essential navigational lights. Air raid wardens were making their rounds to ensure darkness.

The routine plotting of friendly aircraft at the Air Raid Defense Center was suddenly jarred by a report at 12:14 a.m. from the Army radar station on Kauai: "Aircraft bearing 290 true, distant, 240 miles from Oahu." Neither the Navy nor the Army Air force could identify the aircraft as its own. At 12:43 the unidentified aircraft were plotted to be on a steady easterly course toward Oahu. The air defense commander ordered general quarters, and at 1:15 three Navy Consolidated PBY Catalina flying boats were launched to search for any aircraft carrier or seaplane tenders from which these intruders could have originated.

At 1:36 four Curtiss P-40 Warhawk fighters took to the sky to intercept the unknown planes now identified as two separate aircraft on the radar screen. The Hawaiian defense commander then sounded the "full-alert air raid" for the island of Oahu. This was to be the second Japanese attack on the Hawaiian Islands, code named "K-Operation." Had the strike been inspired by a short story written by a U.S. naval officer?

A two-part fictional account of a raid on a Japanese base was featured in the August 1941 Saturday Evening Post. The prewar story, titled "Rendezvous," was written by Alec Hudson, the pen name of then Lieutenant W. J. Holmes of the U.S. Navy. It was subsequently published by MacMillan in a collection of short stories titled Up Periscope.

"Rendezvous" relates the story of a long-range bombing raid by American flying boats on the mythical Japanese port of Bosoko, where troops and transports were assembled for an amphibious operation. Because PBYs did not have the 3,000-mile range necessary to carry out the attack, a plan was devised to refuel the flying boats at the fictional Moab Atoll. The refueling was to be done by three submarines.

Moab was an uninhabited group of barren rocks located less than 1,000 miles from the enemy coast and within the range of PBYs from their home base 2,000 miles away. Three submarines carrying gasoline for the refueling embarked 10 days prior to the raid. The submarines also carried the bombs for the raid in order to reduce the load on the PBYs and thereby increase their range.

The plot thickened when a Japanese destroyer made a routine inspection of the atoll, but the submarine Neptune, the first to arrive at the rendezvous, avoided the enemy ship. The raid was a complete surprise and resulted in a few casualties and other misadventures.

When first submitted to the Office of Naval Intelligence in November 1940, the story was suppressed and retained in departmental files. The author later defended the plausibility of his story by pointing out that Italy was already using submarines to refuel seaplanes. Such refueling operations had also been contemplated by the British. Indeed, a story titled "Attack," featuring a seaplane being refueled by submarine, had been approved by the U.S. Department of the Navy for a major motion picture release.

Subsequently, the story "Rendezvous" was published. It has been suggested by Rear Adm. Edwin T. Layton, a highly informed and well-placed Naval Intelligence figure, that "Rendezvous" had been the inspiration for the Japanese K-Operation. Official Japanese naval records examined by Admiral Layton after the war indicated that plans had been made to follow up their successful December 1941 raid on Pearl Harbor with additional long-range night attacks. These attacks were to be made by patrol aircraft that would be fueled from Sixth Fleet submarines at an atoll west of Oahu.

Several proposals suggested making flights from the Marshall Islands to Pearl Harbor and refueling at French Frigate Shoals, Washington or Necker islands. Other schemes included flights originating in the Gilbert Islands (Makin Atoll) with a refueling stop at Christmas Island. The plan selected was a flight originating at Wotje Atoll (Marshall Islands) with a refueling stop at French Frigate Shoals, which was selected after charts obtained following the capture of Wake Island revealed it to be suitable. It was remote, uninhabited and within striking distance (482 miles) of Pearl Harbor. The charts were up to date regarding navigational information.

Two Kawanishi H8K1s from the 24th Air Flotilla were to be provided for the missions, and they would be based at Wotje Atoll. The H8K, later code-named "Emily" by the Allies, was a newly designed long-range, 24-ton, four engine flying boat. Only two of this type of aircraft existed when the war broke out. They had a range of 3,040 miles with a 1-ton bomb-load, a cruising speed of 184 mph and a service ceiling of 28,700 feet.

About half of the newest Japanese submarines had a water-tight hangar in front of the conning tower for a disassembled Yokosuka E14Y1 two-seat seaplane. The aircraft could be easily assembled and catapulted from the submarine and used for reconnaissance. On December 16, 1941, and again in January and February 1942, submarines launched aircraft made flights over Pearl Harbor. After removing the seaplanes, the submarine's deck hangar could be converted to a gasoline storage area with refueling capabilities. Those submarines would then be dispatched to the lagoon of French Frigate Shoals for the refueling operation.

Submarines I-15 and I-19 were designated the refuelers, and each carried 10-tons of aviation gasoline. I-26 was to accompany them and act as an alternate refueler and picket vessel. I-15 and I-19 would shell any U.S. observation posts they found and enter the lagoon to await the two flying boats. The flagship of the flotilla, I-19, was to be posted about 700 miles southwest of Oahu at "Point M" and was to broadcast a radio beacon for navigational purposes. I-23 would be stationed about 10 miles south of Pearl Harbor for weather observation and rescue purposes should either plane be forced down. In addition, two coastal submarines were to be located 300 miles northwest of Wotje Atoll to help guide the returning raiders to their base. All submarines were to be on station one day prior to the attack.

After extensive training, two H8K1s left Yokosuka, Japan, on February 15, 1942. Their flight took them to Saipan in the Marianas, Truk in the Carolines, and Jaluit in the Marshall Islands before their final stop at Wotje Atoll. March 1, 1942, was selected as the day of the strike since a full moon was predicted---plenty of moonlight was desirable to minimize the hazards of a long water takeoff run.

In the meantime, several events delayed and worked against the success of the raid. A decryption by Commander Joseph J. Rochefort's Naval Intelligence group in Pearl Harbor suggested an offensive action of some sort because radio transmissions had been detected from Japanese submarines east of Midway in the area of French Frigate Shoals. The type of action, however was unclear. The Japanese had also depended, in part, upon daily weather reports from U.S. naval air stations on Midway, Johnson Atoll and the Hawaiian Islands. On March 1, the American code for the weather reports was changed. That left I-23 as the only source of current weather conditions near Pearl Harbor, but I-23 failed to report and disappeared without a trace.

The planned attack was delayed when Japanese planes spotted a U.S. Navy task force, including the aircraft carrier Lexington, nearing the Japanese base of Rabaul on New Britain Island. Japanese naval headquarters at Truk responded by diverting all submarines and surface vessels in the area to intercept the American task force. Two days were spent trying to locate Lexington, and although the American raid on Rabaul was aborted, it did succeed in briefly diverting the Japanese effort. The raid was delayed until March 3.

By early morning on March 3, all was ready. Lieutenant Toshi Hashizume, the pilot of plane No.1, was selected as the flight commander. Ensign Tomaro would pilot plane No.2. After a preliminary briefing, the crew taxied for takeoff, heading into the wind at 3:25 a.m. The weather was clear except for some scattered showers shortly after departure.

Radio transmissions from I-19 were used to correct the planes' positions, and by 2 p.m. they were passing over point M. By 6:30, French Frigate Shoals was in sight and the refueling submarines were waiting inside the lagoon. After a leisurely reconnaissance, the Emilys landed in the lagoon, anchoring astern of the two submarines.

Refueling was complete by sunset, despite adverse winds and a moderate swell. Each plane received 3,000 gallons of fuel. By 9:38 p.m. they were again airborne and enroute to Pearl Harbor. Plane No.1 suffered a hull puncture upon takeoff, but the damage was not serious and it continued on the raid.

The weather remained favorable as Japanese flying boats passed Necker and Nihoa islands. To avoid detection, the planes headed south between Kauai and Niihau before heading to the western tip of Oahu. Neither pilot was aware that American radar was present on the island.

The Emilys closed formation and approached Kaena Point at 15,000 feet. Some clouds were observed over the Koolau mountain range and in the direction of Pearl Harbor. The two flying boats continued on an eastward course to bring them north of Pearl Harbor, where they intended to turn south for their bomb run. Ten-Ten Dock was the Japanese planes' target.

Suddenly, rain obscured the island. Crewmen aboard plane No.1 thought they saw Ford Island, and Hashizume made a rapid turn to the left to circle back over the target. Bombs were released at 2:10 a.m. Tomaro misunderstood the order and continued southward, becoming separated from Hashizume. When the mistake was discovered, Tomaro reversed course and dropped his bombs by direct reckoning at 2:30.

By that time Pearl Harbor was entirely obscured by clouds. Honolulu records report that at 2:10 a.m. four explosions were heard about six miles east of Pearl Harbor. The same cloud cover that obscured the target enabled the raiders to escape. The American P-40s were unable to locate any bandits and returned to their bases, while the PBYs searched in vain for the retiring H8Ks.

On the uninhabited slopes of Mount Tantalus, a thicket of trees was hit by four bombs. The ordinance released by the plane No.2 was apparently dropped harmlessly into the ocean. Because of plane No.1's punctured hull, Hashizume flew directly to Jaluit for repairs, and Ensign Tomaro arrived at Wotje Atoll at 2:45 p.m. Their report concluded that the effect of the raid was "unknown" because of the inclement weather. They did report that a battleship was in dry dock under repair and that a carrier and a cruiser were at anchor in the harbor. Official Japanese accounts of the raid discovered after the war claimed considerable damage done to military installations, along with substantial loss of life.

For a time, the Army and Navy blamed the other's fliers for having accidently released the bombs on Mount Tantalus before returning to base. Many Oahu residents still believe that this is what happened. Experts at the time pointed out that no Japanese plane had the range to make the round trip from Wake or the Marshall Islands. An examination of the bomb fragments, however, identified them as Japanese and identical to those dropped during the December 7, 1941, raid.

On the afternoon of the March 3 raid on Oahu, Captain W. J. Holmes had spent some time with Rochefort, trying to determine what the Japanese submarine activity at French Frigate Shoals meant. Holmes had just fallen asleep that night when he was awakened by his wife, telling him that district Intelligence had ordered general quarters for all hands. On his way back to Pearl Harbor in a rainstorm, Holmes was stopped by a military policeman for an identification check when he heard the explosions echoing off the hills behind Honolulu.

The following morning, Holmes was contacted by Layton, who confirmed what Holmes had suspected---Japanese flying boats had come from the Marshall Islands, refueled at French Frigate Shoals and bombed Oahu. And the Japanese had copied the idea from his story, "Rendezvous."

For all the planning and effort, the raid could hardly be called successful. But it did have important ramifications. When Admiral Chester W. Nimitz, commander in chief of the Pacific Fleet, was reminded of "Rendezvous" by his intelligence officer, Admiral Layton, he directed that the destroyer Ballard be sent to the French Frigate Shoals for surveillance and minelaying operations.

The Japanese had planned a second K-Operation raid prior to the Midway campaign. It was important for them to know the U.S. aircraft carrier strength at Pearl Harbor since they were sure that Yorktown had been sunk, along with Lexington, in the Coral Sea battle a few weeks previously. Japanese Intelligence needed extensive surveillance of the Hawaiian and Midway islands. Ensign Tomaro flew a successful reconnaissance mission to Johnston Atoll, but Lieutenant Hashizume was not so fortunate; he was shot down by U.S. Marine fighters while trying to photograph the facilities on Midway.

The second K-Operation was to be a photographic mission over Pearl Harbor and was scheduled for May 30, 1942. It was cancelled when three submarines (I-121, I-122 and I-123) discovered that French Frigate Shoals was under close observation by planes and warships.

Had Admiral Isoroku Yamamoto, commander of the Japanese Combined Fleet, known that Yorktown had made its way back to Pearl Harbor and was in port with Enterprise and Hornet, he might well have avoided the trap that was about to close on his forces as they converged on Midway in early June 1942.

The voluminous radio traffic concerning the second K-Operation alerted Rochefort to the true objective of the Japanese attack. Decryption by decryption, Midway was identified as the target, rather than a strike south of Fiji, Samoa and New Caledonia, as the intelligence experts in Washington had predicted. Surprise was the key to the American victory at Midway, and denial of French Frigate Shoals may have prevented the U.S. Navy carriers from being discovered by sea-plane reconnaissance, allowing them to slip north of Midway undetected.

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Copyright © Anson H. Stage 1999