They had been holding the wall for seven weeks. After the first Mongol invasion in 1274, every landowning samurai family in Kyushu had been ordered to build — twenty-five miles of stone, five to fifteen feet high, running the entire length of Hakata Bay. It was one of the largest military construction projects in Japanese medieval history, built under government mandate by families who understood that the Mongols would be back. When Kublai Khan came back in 1281 with a force triple the size of anything Japan had ever faced, that wall was waiting.

The numbers were staggering even by modern standards. An Eastern Route Army — nine hundred ships, fifty-seven thousand men — sailed from Korea. A Southern Army — thirty-five hundred ships, roughly one hundred thousand men conscripted from across the Yuan Empire — sailed up from the Chinese coast to join them near Hakata Bay on August 12. Together they formed an armada of approximately four thousand four hundred vessels: the largest assembled in Asia up to that point, larger in raw ship count than the D-Day landings of 1944. They carried weapons the samurai had never seen before 1274: 鉄炮 (tetsuhau) — iron shell grenades that burst with fire and noise — and crossbow bolts dipped in poison. Seven years earlier, these weapons had produced shock and chaos. Now the samurai knew what to expect.

For weeks the fleet could not land. The stone wall held the beaches. Japanese samurai made night raids — rowing out in small wooden boats, setting fire to anchored ships in the dark, climbing aboard to fight in close quarters before the alarm spread, then slipping back into the night. The Mongol crews — mostly Korean and southern Chinese sailors who had themselves been recently conquered — had little loyalty to the enterprise. Morale deteriorated. The fleet sat in the bay, enormous and increasingly desperate.

On August 15, the typhoon struck from the west. Geologist Jon Woodruff's 2014 sediment study confirmed the physical record: typhoon-strength storm deposits in the bay, dating precisely to 1281. The fleet was devastated in a single day. Most of the four thousand ships were sunk or wrecked. Between twenty and thirty thousand soldiers were captured on the beaches afterward; the rest were hunted down across the coast and killed. Only Koreans were spared — they were enslaved. Kublai Khan, according to tradition, wept. He planned a third invasion and died before he could launch it.

The Japanese named the storm 神風 (kamikaze) — 'divine wind,' written with the characters for 'god' 神 (kami) and 'wind' 風 (kaze). Emperor Kameyama had reportedly prayed at Ise Shrine for divine intervention; the storm confirmed everything. The myth of sacred protection took root immediately and deepened across the centuries: Japan had never been successfully invaded, the gods would not permit it, the divine wind would come when needed.

It was this mythology — still alive, still taught — that gave its name, six hundred and sixty-four years later, to the suicide pilots of World War II. Young men sent into the ocean in aircraft loaded with explosives, sent to be the divine wind when the actual weather refused to cooperate. And on August 15, 1945 — the same date the kamikaze was born — Emperor Hirohito broadcast Japan's surrender. The date on which the myth began was the date it finally closed.