Warfare History Network
Pearl Harbor, Asia
Throughout the war in the Pacific, Japanese midget subs made meager contributions.
Here's What You Need to Remember: Paintings and postcards romanticized the midget submarine sailors who lost their lives at Pearl Harbor, but Sakamaki is excluded from any mention. His image is not present in memorial artwork. The Japanese were aware that HA-19 and Sakamaki had both been captured. Having failed in his mission and lived, Sakamaki had become an outcast.
During the early hours of December 7, 1941, five midget submarines of the Imperial Japanese Navy waited to enter Pearl Harbor, the anchorage of the U.S. Pacific Fleet. Their mission was to complement the attack of naval aircraft in dealing a crippling blow to the American naval presence in the Pacific. This ambitious plan failed. Only one craft survived, HA-19, along with one member of its two-man crew, Ensign Kazuo Sakamaki, who became “Prisoner No. 1” of the United States in World War II.
The Midget Submarines
Sakamaki grew up in a tradition-bound Japanese culture that showed deep reverence for family, teachers, and Emperor Hirohito. He later explained, “We were taught, and we came to believe, that the most important thing for us was to die manfully on the battlefield—as the petals of the cherry blossoms fall to the ground—and that in war there is only victory and no retreat.” So, he applied for admission to the Japanese Naval Academy at Etajima and became one of 300 chosen from 6,000 applicants. After graduation, he spent a year at sea, then was promoted to ensign and ordered in April 1941 to report to the Chiyoda, a converted seaplane tender, at the Kure naval shipyard.
Sakamaki had been chosen to take part in the development of a secret weapon, the midget submarine, and would join an elite group called the Special Attack Naval Unit. Cadets received training on the island of Ohurazaki, along with a theoretical education at the Torpedo Experimental Division of the Kure Navy Yard. Classes were also held on the tug Kure Maru and seaplane tenders Chiyoda and Nisshin. This intense training program, which was observed and monitored, caused some cadets to drop out and others to commit suicide. Only the finest survived.
Sakamaki and his fellow crewman, Warrant Officer Kiyoshi Inagaki, learned the ins and outs of their special craft. Each sub held two crewmen because of cramped space. The only entrance was through a 16-inch hatch in the conning tower. The Imperial Japanese Navy called these minisubs Ko-Hyoteki, but those attached to units used the mother sub’s name, such as I-24’s midget. Paul J. Kemp says in Midget Submarines that these were “perhaps the most advanced midget submarines in service with any navy during the Second World War.”
Built in 1938, these cigar-shaped minisubs stretched nearly 80 feet with batteries arranged along each side. They could travel at a speed of 23 knots surfaced and 19 knots submerged, but battery charges lasted only 55 minutes. None of the craft carried generators, so they required recharging by a tender or mother submarine. The torpedo room housed two 18-inch torpedoes, each with around 1,000 pounds of explosives in the warhead. The Japan Optical Manufacturing Company perfected a specialized 10-foot-long miniaturized periscope in secrecy.
In fact, great secrecy shrouded the entire project. The Japanese eventually produced over 400 vessels of four types in a special factory near Kure. Of these, around 60 Type A submarines, the type commanded by Sakamaki, were built. Only key commanders knew details. Dispatches called the craft Special Submarine Boats Koryu (dragon with scales) and other creative names to avoid revealing the true nature of the machines.
When the subs first arrived, one seaman recalled, “After we secured, a barge came alongside each submarine. The barges were carrying strange objects heavily screened by black cloth and guarded by armed sailors and police. The objects were hoisted onto the casing and secured in the cradles—still wreathed in their coverings. We, the ship’s company, were not informed what the objects were. It was only when we proceeded to sea for trials in the Sea of Aki that we learned what we were carrying. The morale on the submarine was incredible.”
Piggy-Backing to Pearl Harbor
In mid-October 1941, maneuvers around islands in the Inland Sea shifted from mid-ocean strategies to invading narrow inlets at night. “When Captain Harada told us to pay particular attention to Pearl Harbor and Singapore,” Sakamaki recalled, “we thought that one group would probably be used against Pearl Harbor and another group against Singapore.” After crewmen graduated and received a 10-day leave, Admiral Isoroku Yamamoto, commander of the Imperial Japanese Navy’s Combined Fleet, spoke to them aboard the battleship Nagato and emphasized the importance of their secret mission against Pearl Harbor.
Five submarines, I-16, I-18, I-20, I-22, and I-24, were to carry midget submarines behind their coming towers. Each minisub would travel piggybacked to the large submarine’s pressure hull with steel belts and was to be released while the mother ship was submerged, enabling it to avoid exposure to the enemy. Some officers opposed the daring plan to use midget submarines to attack American ships in the narrow confines of Pearl Harbor. Captain Hanku Sasaki, commander of the First Submarine Division, wondered if the big submarines could handle so much weight. “There was too much hurry, hurry, hurry,” he criticized after the war.
Commander Mitsuo Fuchida, who led the air attack against Pearl Harbor, scoffed at the entire plan. Others thought the midget submarines rolled and pitched too much. Their conning towers were exposed, and they depended on mother ships for equipment and maintenance. Besides, the element of surprise, which was essential to the success of the air attack, might be compromised if the midget submarines were discovered.
Sakamaki’s minisub was strapped to submarine I-24, which was a long-range reconnaissance type, 348 feet long with a 30-foot beam. Nine thousand horsepower enabled them to reach a surface speed of 22 knots. A telephone line from HA-19’s conning tower connected the two craft, and an attached cylinder between the boats allowed crewmen to stock supplies and make periodic equipment checks en route. On November 18, 1941, Sakamaki wrote home, “I am now leaving. I owe you, my parents, a debt I shall never be able to repay. Whatever may happen to me, it is in the service of our country that I go. Words cannot express my gratitude for the privilege of fighting for the cause of peace and justice.”
The five I-class mother ships and their Special Attack Force minisubs left Kure and headed across the North Pacific to Pearl Harbor on a moonless night. They traveled slowly because of cargo and rough weather, running submerged during the day to avoid detection and surfaced during the evening, maintaining a distance of about 20 miles from each other. Commander Mochitsura Hashimoto, skipper of I-24, remembered many troubles during the ocean trip to Hawaii, including clogged pumps, defective valves, and gear malfunctions.
Once I-24 nearly sank because of a stuck blow-valve, which was freed at the last moment. After surfacing, the crew found a crushed torpedo on Sakamaki’s midget sub and worked all night to replace it with a spare. Hashimoto later said, “This operation may sound easy enough, but in fact, it was far from simple. The lack of space on the narrow upper deck made transporting something weighing over a ton to the after-end of the boat no mean task, say nothing of having to dispose of the damaged torpedo quietly over the side.”
“We were Members of a Suicide Squadron”
The five midget submarines were to be launched off the coast of Oahu where they were to quietly enter Pearl Harbor, navigate around Ford Island counterclockwise, and strike the U.S. battleships moored in the shallow water of the harbor. The minisubs were initially expected to attack between the first and second waves of the air attack. When the American battleships attempted to get underway and escape to the open sea, they might be crippled and clog the mouth of the harbor. “I was astonished and felt as if suddenly petrified,” Sakamaki remembered of the moment the details of the plan were revealed to him. “The effect was like a sudden magic blow.”
Although the plan called for the midget submariners to rendezvous with their mother subs to be recovered on December 8, 1941, about eight miles west of the island of Lanai, Sakamaki realized that the mission was suicidal. The midget submarines lacked battery power to travel such a distance after the assault.
Sakamaki said, “We were members of a suicide squadron. We did not know how we could ever come back.” Rear Admiral Hisashi Mito, who commanded a division of submarine tenders, also remarked after the war that all minisub crewmen “were prepared for death and not expected to return alive.” The name “Special Naval Attack Unit” was a euphemism for suicide attack in the Japanese language. These submariners predated later kamikaze attack units.
By the night of December 6, the mother ships neared Hawaii, and the flickering lights along Oahu’s Waikiki Beach were visible. Landing lights at Hickam Field on Ford Island blazed. Jazz music floated from radios and bars. Everything appeared calm. The large subs fanned out within 10 nautical miles of Pearl Harbor’s mouth and waited for the moment to launch their midget submarines.
“On to Pearl Harbor!”
Shortly before the launch, Sakamaki wrote a farewell note to his father, made a will, and cut the traditional fingernail clippings and lock of hair for the family altar. Then, he put on his uniform, a cotton fundishi (breech-cloth), leather jacket, and a white hachimaki headband. He and Inagaki also sprayed themselves with perfume of cherry blossoms, and both were now ready to die honorably according to the Bushido code of conduct for Japanese warriors.
After loading their midget sub with everything from charts to tools and chocolate, Sakamaki scrawled in his log that the two sailors would go naked instead of wearing uniforms. He also wrote, “Today, I will shoulder one important mission, and diving into Pearl Harbor, will sink the enemy’s warships. I was born a man in our country and the present daring enterprise is really the peak of joy. Disregarding the hardships and bitter dangers of the past year, I have trained and the time has come when I will test my ability here. These tubes [submarines] are the pick of our navy. Moreover, they are the result of the wisdom and skill of several tens of thousands of Japanese. In the present operation, the strength of the crew is even more prepared than the torpedoes and certainly we are all completely affected by a feeling of self-sacrifice.”
A final test before launching, however, uncovered a gyro failure on the minisub. Inagaki made a frantic attempt to repair it—without success. So Sakamaki decided to steer by memory, use a magnetic compass, and rely on periscope checks for location, all foolish but heroic choices. When asked if he wanted to back out, he replied, “On to Pearl Harbor!”
Around 3 am on December 6, Sakamaki and Inagaki squeezed into their black-hulled craft through the attached cylinder. Theirs was the last sub launched. Telephone lines were cut. Heavy steel clamps released. The sailors moved toward Pearl under their own battery power, but trouble shadowed their midget sub from the start.
During the launch, HA-19 took a nose dive and nearly stood on its head. Sakamaki reversed the engines to slow down the descent, while Inagaki shifted ballast around and filled tanks with water to correct the trim. HA-19’s thin pressure hull would crack below 100 feet. It took hours to fix things, which set the nerves of both men on edge. Afterward, they ate rice balls and drank grape wine before raising the ship to check its location through the periscope. They had gone 90 degrees off course and were heading back out to sea.
“My hands were wet with cold sweat,” Sakamaki recalled. “I changed the direction three or four times, hoping against hope that somehow the ship would get going where I wanted to go.” But the tube would not head toward the harbor all night.
The sun rose on Sunday, December 7, and HA-19 still remained outside the harbor’s entrance. Looking through the periscope, Sakamaki saw several U.S. destroyers moving back and forth across the entrance to Pearl. He decided to run the gauntlet, but the sonar aboard the destroyer USS Ward, which had sunk one of the midget subs earlier in the morning, picked up Sakamaki’s HA-19 and dropped depth charges that shook it violently. Sakamaki lost his balance, hit the side of the conning tower, and lost consciousness.
“I came to myself in a short while and saw white smoke in my submarine,” he later wrote in his memoir I Attacked Pearl Harbor. “I changed the speed to half gear and turned the ship around. I wanted to see if any damage had been done to the ship. My aide was all right. The two torpedoes were all right. So I got ready to try again to break through the destroyers.” HA-19 shot ahead. More depth charges came from the Ward. Sakamaki ordered another dive.
When Sakamaki later brought the minisub up to periscope depth, he saw columns of black smoke rising from inside the harbor. Ships were burning. The air attack had succeeded. This prompted him to head straight for the harbor, but the sub went aground on a coral reef, its bow lifting out of the water, propellers spinning in reverse. Most accounts say that the destroyer USS Helm fired shots at HA-19, which missed but knocked the sub loose, damaging one of its torpedoes. Sakamaki, however, said he was told later that a destroyer fired on the minisub, but he “didn’t hear any loud explosions at all at the time.”
The situation worsened. Gas leaks from the batteries made both Sakamaki and Inagaki sick and dizzy. They had to move 11-pound ballast pigs from front to rear on the slippery flooded floor, suffering electric shocks and becoming exhausted from the hot and foul atmosphere. Temperatures reached around 135 degrees inside. They finally freed the minisub but found its torpedo-firing mechanism defective, which now left them weaponless.
Sakamaki wept at the thought of failure and decided to ram a battleship, turning HA-19 into a manned torpedo. “I had set out for Pearl Harbor with the purpose of sinking a battleship,” he later explained to a U.S. Navy intelligence officer. “Although we were able to reach the mouth of the harbor by creeping underneath your bombs falling like rain, our accident was fatal to the submarine. So we determined to proceed without hesitation on the surface of the water, dash into the harbor and climb the (USS Pennsylvania’s) gangway ladder. We hoped to leap onto the deck and die simultaneously with blowing up the enemy warship.”
But this fanciful plan also backfired. Depth charges had disabled the tube’s steering ability, and it spun around erratically. Interior air pressure rose to above 40 pounds. The sailors choked and gasped. Their eyes burned. Lurching made them dazed and weakened. Both seamen finally collapsed, and the craft drifted out to sea.
When Sakamaki finally awoke, he opened the hatch to get fresh air from the cool breeze and saw land. Initially, he thought he had reached the rendezvous point off Lanai. Instead, he was near Bellows Field on the eastern shoreline of Oahu. He tried to start the sub, but its batteries sputtered and went dead. HA-19 then ran aground. The two Japanese sailors decided to set off an explosive charge in the after battery room and swim for it. Sakamaki lit the detonator fuse, and both jumped overboard.
“The water was cold,” Sakamaki later wrote. “The waves were big. I could not move freely and I swallowed salt water. One minute. Two minutes. No explosion. I began to worry about the ship. The midget submarine had to be destroyed. I wanted to go back, but there was no strength left in me. Neither my aide nor I could shout to each other. Strength gradually went out of me. Then I saw my aide no more. He was swallowed up by the giant waves. I lost consciousness.” U.S. soldiers later found Inagaki’s body.
Prisoner No. 1 of the Pacific War
Before dawn on December 8, Lieutenant P.C. Plybon and Corporal D.M. Akui, serving beach duty near Bellows Field about 15 miles east of Pearl Harbor, saw someone swimming toward shore.
“At first we thought it was a big turtle, and then we could see his arms moving as he swam,” said the lieutenant. Corporal Akui fired a rifle shot over the figure’s head. Then Plybon waded into the water and seized Sakamaki, who was wearing only an undershirt and a g-string with 15 cents in Japanese currency sewn into a prayer belt. He dragged the dazed, 127-pound Japanese sailor to shore with the help of Corporal Akui. The Americans shackled his hands and feet, rolled him in an army blanket, and tied him up. Taken to a detention station and interrogated, Sakamaki became “Prisoner No. 1” of the Pacific War.
The humiliated Sakamaki asked only to commit suicide. “My honor as a soldier has fallen to the ground,” he told American intelligence officers. “Due entirely to my inexpert navigation and strategy, I betrayed the expectations of our 100 million people and became a sad prisoner of war disloyal to my country.”
Around 8:45 am, lookouts spotted Sakamaki’s submarine from an observation tower. It was beached on a reef about a mile from shore. A reconnaissance plane with two officers from the 86th Observation Squadron aboard flew out and made a sketch of the midget sub, which they gave to the squadron commander. Several Navy planes then dropped bombs around HA-19 in an attempt to dislodge it from the coral reef. The commanding officer at Bellows Field contacted the Navy submarine depot, requesting that salvage specialists investigate the situation.
Examining the Midget Sub
On the rainy morning of December 10, a crew from Pearl Harbor arrived to salvage the disabled minisub, eventually towing it to shore by attaching a cable to its conning tower. A young radioman named Charles L. Jackson was told by his chief to strip down, swim out the few yards, and take a look: “I didn’t argue,” he commented. “I quickly backed away, then swam to the side of the sub and pulled myself up near the conning tower. I looked back at the chief and he motioned to me to enter the boat. I opened the hatch and nearly fell off the side. The stench was so great, I took a few deep breaths, then climbed on top of the tower to let myself into the small opening of the hatch … As I looked around the darkened interior, I saw the communication gear on the starboard side, a navigation chart and instruments were on the port side.”
Several others joined Jackson on the midget sub. “As I worked on dismantling the radio, the officer crawled forward to examine the torpedoes while the chief went aft into the battery compartment to examine the batteries and propulsion gear,” he said.
During the search, Jackson found an official U.S. Navy chart of Pearl Harbor penciled in with positions of warships. This chart led a board of inquiry to believe that Sakamaki’s midget submarine had actually entered the harbor and traveled around Ford Island before the attack. The theory was later discarded because ideographs gave no sense of the time element, notations seemed too neat and organized, and such a route presented execution problems.
Admiral Husband E. Kimmel, commander of the U.S. Pacific Fleet at the time of the attack, also reasoned, “It didn’t make sense. They could see from the hills, so why risk a submarine going in there?… I would strongly discount anything except the most positive evidence that the Japanese were stupid enough to send a submarine in there merely for the purposes of observing.”
Although experts first hoped to examine HA-19 on land at Bellows Field, they decided to dismantle the vessel into three sections and examine it at Pearl Harbor. A year later, on November 30, 1942, a bronze plaque on a stone base was placed in front of the post headquarters at Bellows Field to honor those men who helped capture Sakamaki and the Japanese minisub.
“Remember Pearl Harbor”
The curious tale of midget sub HA-19 continued. Although it had suffered damage to the rudders, torpedoes, propellers, and bow net cutter, the vessel still remained in good condition and was outfitted as a traveling exhibit without periscope, motor, and most of its original equipment. Damaged parts were repaired with parts from a midget sub rammed in Pearl Harbor by the destroyer USS Monaghan. Electrical fixtures were installed, dummy batteries and motor added, and 22 small windows cut in the hull.
During the war, HA-19 toured 41 states on a trailer, draped in red, white, and blue bunting, promoting the slogan “Remember Pearl Harbor.” Millions bought war bonds and stamps to get a glimpse of the vessel and look inside. Even President Franklin D. Roosevelt inspected it at Mare Island. The traveling HA-19 raised enough money to repair all the ships damaged at Pearl Harbor during the brutal attack.
After the war, HA-19 sat rusting at the Navy Pier in Chicago. It was later sent to a museum in Key West, Florida, and is now on display at the National Museum of the Pacific War in Fredericksburg, Texas.
The Japanese high command spread propaganda that one of the midget subs had sunk the battleship USS Arizona, which had actually been destroyed from the air. One book praised, “Dashing courageously into Pearl Harbor, they completed their task and then calmly awaited death. It came, and they faced it with smiles on their faces. When our thoughts dwell on their gallant deed and we recall their great act of sacrifice, how can we help but become overcome with the deepest feeling of emotion?”
Paintings and postcards romanticized the midget submarine sailors who lost their lives at Pearl Harbor, but Sakamaki is excluded from any mention. His image is not present in memorial artwork. The Japanese were aware that HA-19 and Sakamaki had both been captured. Having failed in his mission and lived, Sakamaki had become an outcast.
40 More Minisubs
Throughout the war in the Pacific, Japanese midget subs made meager contributions. The Pearl Harbor plan had apparently failed. Around 40 more minisubs failed to achieve any notable success at Guadalcanal, the Aleutians, the Philippines, Saipan, Okinawa, or Sydney, Australia. One, however, nearly made history when its torpedo narrowly missed the cruiser USS Boise in the strait between Negros and Siquijor Islands. Aboard the ship at the time was General Douglas MacArthur, commander of Allied forces in the South Pacific.
After the war, Kazuo Sakamaki married, wrote his memoirs, and eventually rose to become Production Chief of Toyota’s Export Division in Nagoya. He later became president of Toyota in Brazil. He died on November 29, 1999, still remembered as “Prisoner No. 1” of the Pacific War.
This article was first published by the Warfare History Network. This first appeared earlier and is being reposted due to reader interest.