Sinking of the Lisbon Maru

Night in the East China Sea: a ship that should never have been invisible

In the first hours of October 1942, a moonless sea wrapped itself around a merchantman that by rights should have been marked and protected. The Lisbon Maru rode the swell off the coast of Zhejiang, near the Zhoushan islands, its steel sides hiding a human cargo the world would later count in sorrow. More than eighteen hundred men—British, Australian, Indian and other Commonwealth soldiers and civilians captured after Hong Kong fell in December 1941—were crowded into cargo holds below decks. They were prisoners, but not signalled as such to the outside world.

The rules of war are supposed to safeguard the captive and the helpless. In practice, wartime secrecy, hasty logistics and a supply chain stretched thin had produced a transport whose identity as a prison ship was known only to its captors. That night, in waters patrolled aggressively by Allied submarines, the Lisbon Maru was as good a target as any cargo vessel.

The voyage from Hong Kong: crowded holds and locked doors

The story begins in late September 1942. Over the course of days, Japanese authorities in Hong Kong consolidated POWs from outlying camps and loaded them into the Lisbon Maru. Men who had survived the surrender and the early months of captivity—already weakened by disease, malnutrition and the routine brutality of internment—were packed into holds designed to carry freight, not people.

The conditions were simple and cruel: wooden bunks layered in tiers, barely any ventilation, limited water and no privacy. Japanese guards kept the holds locked. For the captives, the ship was a moving compound. For the Japanese military, it was cargo—transported without special markings or notifications that might have warned Allied forces.

Whether Lisbon Maru sailed alone or within a small convoy is a matter of record ambiguity; wartime logs are uneven. What is clear is that the vessel left Hong Kong in the last days of September and steamed northward into waters all sides knew were dangerous.

The torpedo in the dark: USS Grouper’s attack

At night on October 1, 1942, the U.S. submarine USS Grouper (SS-214) detected a target and attacked. Grouper’s commander, operating with the standard wartime assumption that enemy merchant and troop shipping were legitimate targets, fired torpedoes. They struck.

The first hits tore open compartments and allowed cold seawater to surge into the lower decks. The Lisbon Maru did not vanish in a single roar; it suffered progressive flooding and a growing list. Above decks, Japanese crew and embarked soldiers scrambled to assess damage and save their own. Below, hundreds of prisoners found the world abruptly, horrifyingly altered.

Accounts from survivors describe the immediate chaos: alarms, unfamiliar commands shouted in Japanese, the sharp smell of diesel and salt. Prisoners pounded at locked hatches. For many, those hatches would not open in time.

Locked below: desperation, escape attempts, and drowning

When a ship is wounded at sea, the first minutes decide everything. For the men in the Lisbon Maru’s holds, minutes became a matter of life or death. Initially, the Japanese guards kept the prisoners locked in. Whether this was rigid military discipline, bureaucratic indecision, or a deliberate measure is disputed among accounts; the effect was the same. As water rose and the list worsened, the desperate found or made ways out—through service hatches, smashed portholes, scuttled woodwork.

Some prisoners reached the deck. Many did not. Those who did find themselves in the water faced a cold ocean, fellow men flailing for life, and the complicating fact that their captors were also trying to save Japanese personnel. Lifebelts and raftage were limited. Scraps of wood, empty crates, floating kit or stripped canvas became lifelines. Men clung to one another, to wreckage, to hope.

Then, survivors later testified, other dangers appeared. Several accounts recorded that Japanese guards and some shipboard personnel fired on POWs in the water. Whether these were isolated incidents or part of a broader pattern aboard and around the Lisbon Maru is a question historians and tribunals examined. What is not in dispute is that many prisoners died in the sea—drowned, shot, or left to the elements—as the wounded ship and surrounding vessels sorted who to rescue and who to leave.

Rescue from small boats: fishermen, escorts, and hard choices

The rescue picture is confusing and uneven. Japanese escorts and nearby naval or merchant traffic picked up some survivors. At the same time, Chinese fishing junks—local, often small wooden craft—rowed into the wreckage and pulled men from the water. Their efforts saved lives; they were a rare, human response to a vast calamity.

But the rescuers could not save everyone. In the hours before Lisbon Maru finally settled beneath the waves on October 2, 1942, hundreds were hauled aboard other ships, wounded and bewildered. Several hundred more were never recovered. Bodies were retrieved later, some washed ashore; others became part of the ship’s last company at the bottom of the sea.

The disparity in survival between Japanese personnel and POWs—many of the former were rescued more rapidly and taken to safety—would become a focus of later inquiries and the bitter memory of survivors. Men who made it to decks of rescuing vessels were often treated first as enemy soldiers; they were then, after cursory medical care, taken to Japanese-controlled ports and re-interred in POW camps in Japan.

Counting the cost: numbers, records, and the problem of certainty

Numbers are never clean in war. Manifests are incomplete; records are lost; memories fade. Still, the Lisbon Maru’s toll has been settled with more specificity than many wartime tragedies. Contemporary British records and subsequent research converge on commonly cited figures: about 1,816 British and Commonwealth prisoners were aboard; roughly 842 of them died as a consequence of the torpedoing, drowning and lethal treatment in the water. That leaves around 974 survivors who were later returned to captivity.

Japanese casualties among crew and soldiers were lower and less consistently reported in Allied accounts, and the sinking removed a single merchant vessel from Japan’s wartime logistics. The material loss mattered, but it was the human devastation—the dozens of men who vanished into the cold—that became the lasting mark.

After the ship sank: captivity, courts, and the slow accounting of justice

Survivors who reached shore or were picked up by escort vessels faced an ugly continuity: freed from the sea, they were still prisoners. Many later died in Japanese camps from wounds, disease or the rigors of forced labor. Others lived long enough to tell their stories.

After the war, tribunals and investigations probed the treatment of POWs in transport and captivity. The Lisbon Maru was part of a pattern—Arisan Maru, Jun’yō Maru and others—where unmarked transports carrying prisoners became targets. Prosecutions specifically tied to the Lisbon Maru were limited in the public record, but the broader body of war crimes trials assessed unlawful killing, mistreatment and failure to protect POWs. Those proceedings helped fold episodes like Lisbon Maru into the post-war record of atrocities and of failures of command and policy.

Policy shifts followed in the long term. The tragedies of unmarked POW transports fed discussions about the need for clearer protections under international law and for better enforcement of the Geneva Conventions’ rules on the treatment and movement of prisoners. In wartime, however, operational secrecy and the strategic aim to choke enemy logistics meant that no quick fix could retroactively protect those already aboard.

The wreck and the memory: a grave that lies at sea

As decades passed, the Lisbon Maru became more than a wartime loss; it became a war grave. The ship’s wreck, lying off the coast of Zhejiang in the approaches to the East China Sea, is treated with reverence and caution. Archaeological surveys have been limited; the site, where many men found their last rest, resists the casual curiosity of the tourist and demands historical solemnity.

Commemoration survives in cemeteries and memorials. Names of those lost appear on Commonwealth lists and in Hong Kong memorial sites such as Sai Wan War Cemetery. Survivor testimony, regimental histories and family remembrances have kept the story alive. Each year, relatives and historians recall the men packed below decks that night, the life they once led, and the way a voyage intended to move cargo instead recorded a human catastrophe.

What Lisbon Maru left behind

The Lisbon Maru sits in the record as a confluence of wartime logic and human cost. It shows how military necessity, concealment and the absence of safeguards can turn transport into tomb. It shows too the small mercies—Chinese fishermen hauling men aboard, rescuers pulling a sodden survivor onto a plank—that interrupted the larger evil.

Histories of the Pacific War list tonnage and convoy losses in cold columns. The sinking of the Lisbon Maru refuses to be reduced to a single figure. Behind the manifest were names, faces, letters never sent, and futures denied. The ship’s loss prompted a hard lesson: that the rules that separate combatants from the defenseless matter most when the ocean is dark and a torpedo finds its mark.