Japan Hid Its Pearl Harbor POW. He Survived and Left a Tale of Resilience.

Eighty years after the Pearl Harbor attack on Dec. 7, 1941, the story of Japan’s first POW is kept alive by his brother, who is 88. The story raises questions that come up in every war, such as how far the duty of a soldier extends and what kind of treatment is due the enemy.

What President

Franklin D. Roosevelt

called “a date which will live in infamy” is remembered for the Japanese bombers that attacked U.S. Navy ships. But in a lesser-known adjunct to the air raid, Japan also sent five two-man midget submarines to Pearl Harbor in the hopes of torpedoing U.S. warships.

One carried Ensign Kazuo Sakamaki. He was the second son of parents who had 11 children including little Nobuo, who later took his wife’s family name, Matsubara.

A few hours before the bomber raid began Sunday morning, Mr. Sakamaki’s midget sub was launched from its mother submarine 10 miles off Pearl Harbor.

Mr. Sakamaki recalled in a 1949 memoir the parade of disasters that followed. His submarine tumbled flailing into the water, its gyrocompass already broken. By the time the craft was righted, it was off course, and the men had to approach Pearl Harbor virtually blindly, occasionally poking the periscope above the surface to check their course. Then Mr. Sakamaki was knocked unconscious by a shock wave as depth charges exploded nearby. Even an attempt at a suicide attack failed because the men couldn’t reach a U.S. warship to ram.

By early Monday, the submarine was stuck on a reef and the men had to abandon ship. Mr. Sakamaki wrote that he jumped into the sea and after a while lost touch with his comrade, who would be found drowned. Later that morning, Mr. Sakamaki found himself on Waimanalo Beach in Oahu, where two American soldiers grabbed his arms and led him away.

Back in Tokushima prefecture, Nobuo heard the news of Pearl Harbor and never dreamed his brother was involved. After initially saying Kazuo was dead, the navy sent a higher-ranking officer to confide that the ensign was missing. The family was ordered to keep it a secret.

On March 6, the Imperial Headquarters announced the names of nine men who died in the submarine attack at Pearl Harbor. The Japanese media praised them as “hero gods.” But it didn’t add up to young Nobuo. “Nine people for five boats. It seemed odd to both adults and children,” he recalled. He began to suspect there was a 10th man no one wanted to talk about—his brother.

Jo Toyoda, a Naval Academy classmate of Kazuo, wrote in a 1977 memoir that classmates knew one of their own was a POW. Mr. Toyoda recalled some saying things like, “That Sakamaki idiot ought to kill himself. If he sticks around, he’ll be the shame of our class.”

Mr. Sakamaki at first felt the same way. He recalled telling his interrogator in Honolulu, “Shoot and kill me in front of the burning Arizona!”

Instead, the U.S. held him for a few months in Hawaii before transferring him to POW camps on the mainland.

It was a time when hatred of Japan ran high.

At a private gathering of old naval comrades in 1986, Mr. Sakamaki said it was still too sensitive to report on his experiences. He mentioned that he had planned to testify at the Tokyo Trials in defense of Japanese soldiers accused of abusing American POWs—presumably to make the case that Americans abused Japanese POWs as well—but was stopped by the judge because it would pose an international issue.

In 1989, Kyodo News published an article about a copy of an American report on treatment of Japanese POWs. It said the report recorded an incident on Christmas Eve in 1941 in which someone in Honolulu sent coffee to Mr. Sakamaki and a Japanese woman detained in a cell next to him. The report cited Mr. Sakamaki as saying that he recognized it as a trap, but the woman was stricken and a doctor was called in. The outcome of her case wasn’t known, and Mr. Sakamaki declined to comment to Kyodo.

Mr. Sakamaki wrote more about his time as a POW on the mainland. Seeing the trains passing by his camp carrying vast stores of modern weapons, he began to realize how foolish his country had been. Arriving as a nationalist who wanted only to die for Imperial Japan, he decided to live out the war and became a POW camp leader who looked after the other prisoners.

Perhaps the harshest treatment he spoke of came around the time of the war’s end at Camp Kenedy in Texas. Mr. Toyoda, the classmate, was a POW at the same camp. The commander held a grudge because he had been demoted over the Pearl Harbor attack, and he put the two men in scorpion-infested cells, Mr. Toyoda recalled. Mr. Sakamaki mentioned the episode in his 1986 speech, saying he had little food for days.

Early in 1946, Mr. Sakamaki was repatriated to Japan. He later described receiving a letter telling him to commit ritual suicide, but Nobuo also remembers that neighbors welcomed him home. Curious people lined up to see the miraculously returned ensign. His father greeted the visitors while Kazuo stayed in the shadows.

“For several years afterward, I had the feeling that I had to stay one step back” because of the lingering stigma or indignity associated with POWs, recalls Nobuo. “Our friends and neighbors sincerely said, ‘It was good he came back alive,’ but all we could say was ‘Thank you very much.’ We couldn’t say, ‘We are happy,’ because many people died in the war.”

Kazuo put his memories into two books written in the four years after the war but rarely spoke to his family or anyone else about being a POW. He went into a career in business, eventually rising to head a Toyota Motor Corp. subsidiary in Brazil. He died at the age of 81 in 1999.

Nobuo became a world-history teacher. Now retired, he lives in Tokushima city. He is the last survivor of the 11 siblings and lives not far from the place where that naval officer came 80 years ago. The old house was torn down last year.

He believes the tale of a POW who was ready to die but made a productive life instead is worth retelling. “It’s one example of how you have to go forward and make an effort to build peace, knowing how humanity is precious,” Nobuo says.

Write to Chieko Tsuneoka at chieko.Tsuneoka@dowjones.com