The seventeenth of February, nineteen forty-four. It is still dark over a lagoon in the middle of the Pacific when about seventy American fighters come in low over the water. Below them, more than forty Japanese ships ride at anchor. On the airfields, hundreds of planes sit in rows. Many of the pilots who should be flying them are ashore, on leave. The radar on the islands cannot see aircraft flying this low. Nobody sounds the alarm in time.

If that sounds familiar, it should. Twenty-six months earlier, Japan did exactly this to the United States at Pearl Harbor. This is the story of the day it came back to them, at Truk, the base the Americans themselves called the Japanese Pearl Harbor.

It is built from the American carrier air group reports, from the Japanese navy's own records of where each of its ships went and how each one died, and from the loss tallies of both sides. And the further you follow those records, the more literal the payback gets. One of the ships at the bottom of this lagoon had refueled the carriers that attacked Pearl Harbor. One of the cruisers that died that day was the ship where Japan's submarine captains were first briefed on the Pearl Harbor plan. And the Americans did one thing at Truk that the Japanese had failed to do in Hawaii. By the end, you'll see what it was, and why it mattered more than any ship.

The American admirals were nervous about this place, and for two years they had reason to be.

Truk is not one island. It is a ring of coral reef about a hundred and forty miles around, and inside it lies a sheltered lagoon dotted with green volcanic islands. Japan had held these islands since nineteen fourteen. Before the war it built them into the main anchorage of its Fourth Fleet, and after Pearl Harbor the Combined Fleet itself used Truk as its forward base. There were five airfields, a seaplane base, fuel tanks, repair shops, and room in the lagoon for an entire battle fleet.

Look at it on a map and you see why it mattered. Truk sat almost in the middle of everything. It was the hub between the home islands and the oil and rubber of the south, the staging point for aircraft flying down to Rabaul, and the only major Japanese airfield within range of the Marshall Islands, where American Marines and soldiers had just landed.

The Americans had almost no photographs of it. For two years Truk was a name on a chart and a reputation. Newspapers called it the Gibraltar of the Pacific. Navy planners assumed it bristled with guns. The truth was very different. Japan had poured its money into ships, not fixed defenses, and real fortification of Truk only began in late nineteen forty-three. The anti-aircraft guns were few. The radar was poor and badly manned. And the Japanese navy and army commanders on the islands still ran separate air defenses that could barely talk to each other.

But nobody on the American side knew that yet. And to find out, someone had to go and look.

On the fourth of February, nineteen forty-four, two Marine Corps Liberators flew up from the Solomons, more than eight hundred miles each way. They were flown by Major James Christensen and Captain James Yawn, and they arrived over Truk at twenty-three thousand feet in the early morning. Through gaps in the cloud their cameras caught the giant battleship Musashi, an aircraft carrier, cruisers, destroyers, submarines, and a crowd of cargo ships.

The Japanese saw them too. And the commander of the Combined Fleet, Admiral Mineichi Koga, drew the obvious conclusion. Planes that could photograph Truk today meant carriers that could bomb it soon. He had already been pulling his heaviest ships out of the lagoon since the autumn. Now he finished the job. By the tenth of February, Musashi and the fastest units of the fleet had gone, west to Palau and north to Japan.

This is the part of the story that makes the comparison with Pearl Harbor honest. On the seventh of December, nineteen forty-one, the Japanese had come looking for the American aircraft carriers, and the carriers weren't there. Now the Americans were coming for the Japanese battleships, and the battleships weren't there either.

What was left behind was everything else. Tankers, freighters, ammunition ships, transports full of troops, old cruisers, destroyers, repair ships. Hundreds of aircraft. And the pilots of two air flotillas, who had spent weeks on high alert after the Liberators were spotted, and who had just been given shore leave.

One more warship left in time, or thought she had. The light cruiser Agano had been badly damaged months earlier and patched up at Truk. On the evening of the fifteenth of February she sailed for Japan with the destroyer Oite. The next afternoon, about a hundred and sixty miles north of the lagoon, the American submarine Skate put two torpedoes into her. Oite pulled five hundred and twenty-three of Agano's men out of the water, turned around, and headed back to the one place she thought was safe. Truk.

Against Truk the Americans sent Task Force Fifty-Eight under Vice Admiral Marc Mitscher, with Admiral Raymond Spruance in overall command. Nine aircraft carriers. Five of them were the big fleet carriers Enterprise, Yorktown, Essex, Intrepid and Bunker Hill. Four were light carriers. Together they carried more than five hundred planes, screened by battleships, cruisers and destroyers. Submarines were already waiting outside the reef for anything that tried to run.

The first launch began about ninety minutes before sunrise. It was not a bombing raid. It was a fighter sweep, about seventy Hellcats with one job: take the sky away from the Japanese before the bombers arrived.

More than three hundred Japanese aircraft were at Truk that morning, but only about half of them were ready to fly. The pilots scrambled with only minutes of warning. About eighty Zeros got into the air, many of them climbing out of their airfields straight into Hellcats that already had height and speed. As many as thirty Zeros were shot down. Others were caught on the ground, taking off or still parked, and strafed where they stood.

By late morning there was only scattered resistance in the air. By the afternoon there were almost no Japanese aircraft left to fight. In a few hours, the thing that made Truk dangerous, its air power, was gone.

Behind the fighters came the Avengers and the dive bombers. Avengers from Enterprise and Intrepid dropped fragmentation and incendiary bombs on the runways at Eten Island and the seaplane base on Moen. Dive bombers cratered the airstrips and wrecked the hangars. Then the strikes turned to the ships.

This is the moment the whole raid was built around. The lagoon was full, and almost nothing in it could move fast enough to matter. The merchant ships had no fighter cover and no warning, only the anti-aircraft guns on the islands around them. Strike after strike rolled in, roughly once an hour, for two days.

That morning, crews in American Avengers circling over Dublon Island took photographs that are still the best record of the raid. They show the lagoon from above, the town and the docks, the ships scattered across the anchorage, and the smoke beginning to rise.

One of them shows the Aikoku Maru. She was an ammunition ship, loaded with shells and carrying troops bound for Rabaul. She had already been hit by bombs from Intrepid's planes when Lieutenant James Bridges brought his Avenger in low and put a torpedo into her side. The torpedo set off the ammunition in her forward hold. The explosion tore off her bow, and she sank in about two minutes, taking most of the nine hundred and forty-five people aboard with her. Bridges' Avenger was too close. The blast swallowed the plane and all three men inside it.

It wasn't one ship. All across the lagoon tankers burned and freighters settled into the shallows. Fuel stores ashore went up in flames. In the second and third strikes of the day, the American air group reports began listing the enemy's apparent mission with a single word. Escape.

And one group almost made it.

Before dawn, at half past four, a small convoy had slipped out through the North Pass heading for Japan. It was led by the light cruiser Katori, with the armed merchant cruiser Akagi Maru, the destroyers Maikaze and Nowaki, and a minesweeping trawler.

Katori was not just any cruiser. For most of the war she had been the flagship of Japan's submarine fleet. On the eleventh of November, nineteen forty-one, her admiral called his submarine commanders aboard her and briefed them on the plan to attack Pearl Harbor. Four weeks later, as Japanese submarines lay in wait around Oahu, she was their flagship, directing them from Kwajalein.

Now carrier planes from Yorktown, Intrepid, Bunker Hill and Cowpens found her group in open water. They sank the Akagi Maru, put a torpedo into Katori and damaged Maikaze. The cruiser was burning and listing. More strikes would have finished her within the hour.

But Admiral Spruance wanted something else. He wanted a surface battle. So Mitscher called his planes off, and Spruance went to sea himself, hoisting his flag in the brand new battleship New Jersey. With her came her sister ship Iowa, the heavy cruisers Minneapolis and New Orleans, and the destroyers Bradford and Burns. Some of Spruance's own staff thought it was reckless, an admiral risking the fleet's newest battleships to do what aircraft could already do. Spruance went anyway.

Two of those cruisers had a score of their own to settle. On the morning of Pearl Harbor, Minneapolis had been at sea on gunnery practice eight miles off the harbor. New Orleans had been moored inside it with her engines torn down for repair, her crew breaking the locks off the ammunition boxes and firing back at the attacking planes with rifles and pistols.

Early in the afternoon the American force found the Japanese ships northwest of Truk. Maikaze turned to fight. She fired a spread of torpedoes that ran straight between New Jersey and Iowa and missed them both. Then the cruiser fire found her. A fire started aft, probably reached a magazine, and at a quarter to two Maikaze went down, still firing, with every man aboard.

Iowa took Katori. From about fourteen thousand yards she fired forty-six sixteen-inch shells and more than a hundred five-inch rounds into the crippled cruiser, straddling her with every salvo. Katori fired back with torpedoes. They missed. After Iowa's fourth salvo she heeled over to port, showing great shell holes in her side, and sank stern first about forty miles northwest of Truk. American sailors saw a large group of survivors in the water where she went down. None were picked up.

The ship where the Pearl Harbor submarine plan was briefed had been sunk by an American battleship. It was the only time Iowa or New Jersey ever fired their main guns at enemy ships.

One ship got away. The destroyer Nowaki ran for it at full speed, straight into the glare of the afternoon sun. Both battleships chased her at more than thirty knots and opened fire at thirty-five thousand yards, then kept firing by radar out to thirty-nine thousand. At twenty-two miles, those were the longest-range shots American battleships ever fired at an enemy ship. Shells landed all around her. Nowaki kept running, and she made it home.

That should have been the end of the first day. It wasn't.

As night fell, twelve Avengers of Torpedo Squadron Ten took off from Enterprise, led by Lieutenant Van Eason. Nothing like it had been tried before. It was the first night radar bombing attack ever launched from an American carrier. Their air group had qualified for night carrier landings only weeks before. Flying low over the black water, they found the ships in the lagoon by radar and bombed them at minimum altitude in the dark.

The Navy's own history credits that one night strike with nearly a third of all the shipping sunk at Truk.

Their targets that night included a ship with a direct line back to Pearl Harbor.

Anchored northwest of Fefan Island was the tanker Shinkoku Maru. In late November, nineteen forty-one, she had sailed from Hitokappu Bay in the Kuril Islands with the oilers that kept Admiral Nagumo's six carriers fueled all the way across the North Pacific to Hawaii. Yamamoto's orders said that if refueling failed in the winter seas, half of those carriers would have to turn back and the attack would go ahead without them.

She had already been hit at Truk by a bomb from Yorktown's dive bombers and a torpedo from Bunker Hill's Avengers. Then, in the early hours of the eighteenth of February, Enterprise's night bombers came over, and a near miss beside her engine room opened her hull. She settled upright on the bottom of the lagoon, where she still lies.

Enterprise had been on her way home to Pearl Harbor that December morning in nineteen forty-one. Some of her planes flew into the middle of the attack, and some of them never came back. Twenty-six months later, her bombers helped finish off one of the ships that had fueled it.

The Japanese did hit back. Through the night, small groups of bombers probed the task force, one, two or three planes at a time. One lone twin-engine bomber got through to Intrepid and put a torpedo into her stern. Eleven men were killed and her rudder jammed hard over. Her crew steered with the engines until the wind overpowered them, then rigged a makeshift sail out of canvas and hatch covers. The crippled carrier limped all the way back to Pearl Harbor.

The next morning the strikes went in again. And the destroyer Oite, the ship that had stopped to pull five hundred and twenty-three men from the cruiser Agano, finally reached the North Pass, right in the middle of it. An aerial torpedo hit her amidships. She broke in half and sank almost at once. About twenty men survived. Almost every one of the Agano survivors she had rescued died with her.

By the afternoon of the eighteenth, it was over. Task Force Fifty-Eight turned away, and Truk was never again a working base for the Japanese fleet.

So here is the reckoning, side by side.

At Pearl Harbor, the Japanese sank or ran aground eighteen ships, destroyed one hundred and eighty-eight aircraft, and killed two thousand four hundred and three Americans. It cost them twenty-nine planes.

At Truk, the Americans sank two light cruisers, four destroyers, three auxiliary cruisers, six other auxiliaries and thirty-two merchant ships, close to two hundred thousand tons of shipping in all. They destroyed around two hundred and fifty Japanese aircraft. More than four thousand five hundred Japanese were killed. It cost the Americans twenty-five planes and forty men.

Japan lost twenty-nine planes at Pearl Harbor. America lost twenty-five at Truk.

But the numbers aren't the real difference. Two things are.

The first is what happened to the ships afterward. At Pearl Harbor, every battleship except Arizona and Utah was raised from the mud, and six of them went back to war. One of them fired on the beaches at Normandy. Five of them were in the battle line at Surigao Strait that sank a Japanese battleship. The ships sunk at Truk never came back up. Japan never raised them, and by nineteen forty-four it could not build new ships fast enough to replace them. The ships lost in those two days were almost a tenth of all the Japanese shipping lost in the eight months from November nineteen forty-three to the end of June nineteen forty-four.

The second is the thing the Japanese didn't do at Pearl Harbor. When Nagumo's planes left Oahu, they left the fuel tank farms and the repair yards untouched. Those tanks kept the Pacific Fleet at sea through the months that followed. At Truk, the Americans did not make the same mistake. Some seventeen thousand tons of stored fuel went up in flames, along with tankers that Japan could not replace. It was part of the fuel squeeze that, by Leyte Gulf eight months later, forced the Japanese fleet to sail in separate pieces.

Tokyo knew what it had lost. The admiral in charge of Truk, Vice Admiral Masami Kobayashi, was relieved of his command two days after the raid.

After that, the Americans didn't even bother to invade. They hit Truk again from the carriers in April, kept bombing it from the air, and let their submarines cut the supply lines. The garrison was left behind the front, waiting for ships that no longer came. By the summer of nineteen forty-five, one historian wrote, Truk had been reduced to starving impotence.

There is one last thing about Truk.

The ships are still there. Lying in clear, warm water, some of them less than fifty feet down, the tankers, freighters and transports of February nineteen forty-four sit upright on the bottom of the lagoon. Jacques Cousteau's team explored them in nineteen sixty-nine, and since then Truk Lagoon has become one of the most famous wreck dives in the world. Divers swim through holds still loaded with aircraft, trucks, tanks, shells and mines. The Shinkoku Maru is one of them, a tanker from the Pearl Harbor fleet, covered now in coral.

Many of the men who served in those ships never left them, and the wrecks are Japanese war graves. The forty Americans who didn't come home from those two days are part of this lagoon's story too, among them Lieutenant Bridges and his two crewmen, lost in the flash of the Aikoku Maru.

At Pearl Harbor the Japanese caught an American fleet at anchor, with its planes on the ground and its sailors at rest, and they called it a victory. Twenty-six months later, at Truk, the Americans did the same thing back, and did it more completely.