The 80th anniversary of D-Day

Eighty years ago, in June 1944, a massive invasion force landed on Axis enemy soil, opening a beachhead that led the following year to ultimate victory for the World War Two Allied forces.

Last week we celebrated the D-Day invasion of Europe with appropriate commemorative events and reminiscing.

But the Normandy invasion’s D-Day twin, half a world away, has gone almost unnoticed this year. When the Allies landed on five beaches in France on June 6, 1944, an American invasion force that within days numbered nearly 100,000 was simultaneously steaming toward the Northern Marianas and the target Japanese-held island: Saipan.

The taking of Saipan has been likened in importance to the Normandy invasion. In July 1944, after the 24-day battle that culminated in American occupation of Saipan, a report from the Chief of the War Guidance Department of Japanese Imperial General Headquarters, Colonel Sei Matsutani, stated that the American victory on the island destroyed all hope for Japan to win the war. After the Japanese surrender the following year, many Japanese leaders agreed with him: Saipan was the turning point.

The Northern Marianas lie about equidistant north of New Guinea, east of the Philippines, and (supremely important) south of Japan. Saipan is the largest of the archipelago’s islands, at about 45 square miles, and as such the Japanese had fortified it and built an airfield in its southwest sector.

For the United States, Saipan’s crucial importance lay in the fact that it is situated about 1,200 miles from Japan’s major industrial cities, well within the 1,600-mile effective range of the new United States B-29 Superfortress bombers. Both the U.S. and Japan knew well the significance of that geography. The immense American industrial complex was turning out the giant bombers at an unbelievable pace.

Japan’s vulnerability to overwhelming American bombardment from the air was why Colonel Matsutani believed Japan was doomed by the loss of Saipan.

Following two days of heavy shelling by seven American battleships, American marines and Army troops began landing on Saipan’s southwest coast the morning of June 15. Eight thousand troops waded ashore in the first 20 minutes; by nightfall there were 20,000; and within a few days the force had swelled to nearly 100,000, including one army and three marine divisions and numerous construction and accessory battalions.

Japanese defenders numbered about 30,000. Their supplies, limited to begin with, shrank inexorably since the American fleet controlled the coast, preventing resupply by Japanese transports.

With superior numbers, weaponry, ammunition, and other supplies, the Americans pushed the Japanese troops steadily northward up the 12-mile length of the mountainous island. The terrain made the going difficult, and the defenders holed up in caves hidden by brush.

Adding to the resistance was the Japanese tradition not to surrender or be taken prisoner. As a result, when the battle ended 24 days after the invasion, nearly the entire 30,000 man Japanese garrison lay dead, many from suicide. Thousands of Saipan civilians perished as well; many of them had sought refuge in the same type of mountain caves that housed the Japanese troops, and they died in the horrific flame-throwing onslaught that the Americans employed to eliminate the enemy.

As the Americans approached the north tip of Saipan at Mardi Point after pushing their way up the island, more than 1,000 Japanese civilians, mostly women and children, believing their nation’s propaganda about the supposed cruelty of American troops, threw themselves off 200-foot-high Suicide Cliff and Banzai Cliff rather than be taken prisoner.

American casualties on Saipan totaled about 14,000, including 3,426 killed. Well below the nearly total destruction of the Japanese force, but certainly significant enough to cause American leaders to do some math.

The willingness of Japanese soldiers and civilians on Saipan to take their own lives rather than be taken prisoner induced American strategists to create the “Saipan ratio”—one killed American and several wounded for every seven Japanese soldier deaths—to be used to calculate the human cost of the planned American invasion of Japan’s home islands. The initial calculation came up with 2,000,000 American casualties, including 500,000 deaths.

While the calculation shrank over the following months, it nevertheless figured heavily in the decision to drop the atomic bombs a year later on Hiroshima and Nagasaki as an alternative to a naval invasion like those at Normandy and Saipan.

Also figuring into American dominance at Saipan: when the marines and Army troops landed, the Japanese military and naval leadership determined it was necessary to try to dislodge them, or at least disrupt American supply lines to the island. That effort led within a few days to the Battle of the Philippine Sea, or as U.S. aviators came to call it, “the Great Marianas Turkey Shoot.”

On June 19, four days after the troops landed, American pilots shot down more than 300 attacking Japanese planes while losing fewer than 30 of their own. U.S. submarines sank two Japanese carriers. The overwhelming victory was the greatest carrier battle of the war. When it was all over, the Japanese had lost their ability to fight in the air, at the cost of three aircraft carriers and a total of 480 aircraft, as well as most of their well-trained pilots.

A Japanese admiral wrote, “It will be extremely difficult to recover from this disaster and rise again.” Sixteen weeks later the Battle of Leyte Gulf stamped an exclamation point to his comment.

Because of its decisive role in the War for the Pacific, Saipan’s D-Day deserves more recognition than it’s receiving on its 80th anniversary.

Rick Morain is a reporter and columnist with the Jefferson Herald.