To Vicente Sydiongco, the first shells sounded like thunder. It was Oct. 20, 1944, and a typhoon had struck the central Philippines island of Leyte the night before. Then Sydiongco heard the secondary explosions, and he realized this was no typhoon. He knew then that, true to the promise of Gen. Douglas MacArthur, the Americans had returned.

Capt. Paul Austin of Fort Worth, Tex., was one of those Americans who hit the beaches of Leyte Gulf 40 years ago as part of MacArthur's drive to recapture the Japanese-occupied Philippines and split Tokyo's World War II empire in half. The operation, the general wrote later in his memoirs, would become a springboard "for the final assault on Japan itself."

Austin's unit came under heavy Japanese artillery and machine-gun fire that day as the Americans established their beachhead, but the hardest fighting was yet to come. Austin, then a company commander, would later lead a bayonet charge and engage the Japanese in hand-to-hand combat.

Today, he and about 400 other veterans from the United States, Australia and Japan gather here with Sydiongco and thousands of Filipino veterans to mark the 40th anniversary of the Leyte landing.

For the Americans it was "A-Day," a day of triumph for MacArthur and the culmination of a 1,500-mile seaborne jump by about 200,000 troops that has been described as one of the most daring amphibious operations ever conceived.

It was also the prelude to what American historian William Manchester has called "the greatest naval battle in history," the Battle of Leyte Gulf, in which an American armada routed the Japanese fleet a few days later.

By the time it was over, the Japanese had lost four aircraft carriers, three battleships, eight destroyers, six heavy cruisers and three light cruisers in an unsuccessful bid to trap and bombard the American landing force. By comparison, the U.S. naval forces under Adms. William Halsey and Thomas Kinkaid had lost one light carrier, two escort carriers and three destroyers in the battle, which had involved a total of 282 warships on both sides.

For the Japanese, Manchester wrote, "Leyte had been a catastrophe." They lost 65,000 crack troops, the backbone of their fleet and virtually all of their Air Force except for kamikazes, which made their debut during the Philippine campaign.

In commemoration of the events at Leyte, veterans of the U.S. 96th and 24th divisions, Australia's Allied Land Forces and the Japanese 16th Division will tour battle sites, lay wreaths to honor their fallen comrades and watch a joint amphibious landing exercise by combined units of the U.S. and Philippine armed forces.

MacArthur's landing, in which he waded to shore accompanied by Philippine President Sergio Osmena and top generals and aides, is to be reenacted with an American officer playing the part of the U.S. commander in the Pacific, who died in 1964.

Vice Adm. James Hogg, the commander in chief of the U.S. 7th Fleet, has been chosen to represent the Pentagon at the ceremonies.

According to James Hofrichter, 63, one of the organizers of the veterans' trip here, more than 180 U.S. officers and men who fought in the Philippines are taking part in the ceremonies.

Many American veterans feel the Leyte landing anniversary has been overshadowed by the commemoration earlier this year of the 40th anniversary of the Allied invasion of France at Normandy beach that helped defeat Nazi Germany, Hofrichter said. But the memories of the U.S. Pacific theater veterans are no less vivid, and the suffering of many of them at the hands of the Nazis' Japanese allies no less real.

Conversations this week with 10 American veterans who fought under MacArthur also show that forgiveness does not come easy. Some want nothing to do with the Japanese veterans here and never have reconciled themselves to the postwar partnership between the United States and Japan.

"When I'm over here and I think about the buddies I helped bury on Leyte, I can't help it," said James Frederick, 59, of Arlington, Tex. "It's still embedded in my mind."

One of the returning veterans who suffered most was Richard Deuitch, 65, of Garrett, Ind., a former 2nd class petty officer taken prisoner by the Japanese in 1942 after being wounded on Corregidor. A survivor of the infamous "Bataan Death March," in which thousands of captured American and Filipino soldiers died, Deuitch spent a year in a prison camp in the Philippines and about two years in a labor camp in Japan until the war ended.

Out of 405 prisoners of war in his group in Japan, he said, "133 of us walked out." Thousands of American prisoners were starved, beaten or tortured to death, he said, and others suffered unspeakable cruelties at the hands of their captors.

Filipinos also suffered severely, especially after MacArthur began his drive to recapture the Philippine Islands and was welcomed by the populace as a returning hero.

According to Manchester, nearly100,000 Filipinos were murdered by rampaging Japanese troops in Manila after MacArthur's forces put the Philippine capital under siege. Hospitals were set afire, women of all ages were raped and even babies were mutilated or slaughtered by the Japanese, he wrote. Some American veterans never have reconciled themselves to the postwar partnership between the United States and Japan.

When the siege ended, Manila lay in ruins. Of allied cities during World War II, only Warsaw suffered greater devastation.

"The young people of today don't know about that anymore," former foreign minister Carlos Romulo said in a recent interview. "They don't know what we went through."

Romulo, now 85 and in poor health, was with MacArthur on the small fortified island of Corregidor at the entrance to Manila Bay in March 1942 when the U.S. general, facing capture by the Japanese, left the Philippines with the promise, "I shall return."

Then a young brigadier general, Romulo also accompanied MacArthur during his triumphant landing at Leyte. Like many other Filipinos, Romulo still reveres the U.S. general. Today his figure can be seen behind MacArthur's in a group of statues that form a monument to the Leyte landing at the stretch of shoreline code-named "Red Beach" near Tacloban.

"I had bought a pair of boots in San Francisco to wear upon my entry in the Philippines," Romulo recalled in the interview at his Manila home. "But I didn't know MacArthur would make us jump in the water and make all of us wade. My main worry was my new boots." The boots are now in a museum.

Romulo, who stands about 5 feet tall, also recalled the joke of an American columnist at the time that if it were true MacArthur waded into waist-deep water with Romulo behind him, then Romulo must have drowned.

Another who remembers that landing is Col. Lee Telesco, an American intelligence officer who arrived on Leyte by submarine two weeks before MacArthur. He now serves as a senior executive in a large Philippine corporation. His most vivid memory, he said, was the "massive firepower of the more than 600 ships of MacArthur's fleet as they bombarded Red Beach" before the landing. When the troops came ashore, he said, he and his comrades among the Philippine resistance guerrillas wept tears of joy.

One of the guerrillas, Silverio Vergara, now a 61-year-old worker at a Tacloban ice plant, recalled that overjoyed Philippine civilians ran down to the beaches to help pick up the wounded while the outnumbered Japanese retreated inland to Buga Buga hill to make a last stand.

"After all the killing by the Japanese, we were liberated by the American forces," Vergara said. "The new generation doesn't understand, but the Filipinos who were there can never forget what happened."