The Japanese had made many defense preparations after the failed first invasion by the Yuan navy.
Many forts have been constructed along the coast line and samurai further trained, perfecting their swordsmanship.
Kublai Khan had planned another invasion of Japan in early 1280 and had ordered his shipbuilders to rebuild the whole fleet within a year.
Many of the ships had been poorly made in the short time available; many are flat-bottomed river boats requisitioned by the Emperor.
Nine hundred Yuan ships are gathered in Korea by early 1281; the force is called the Eastern Route Army.
Crewed by seventeen thousand sailors, they transport ten thousand Korean soldiers and fifteen thousand Mongols and Chinese.
The Southern Route Army, meanwhile, is assembled just south of the Yangtze River, in China.
It is said to have consisted of one hundred thousand men on thirty-five hundred ships.
As before, Iki and Tsushima islands fall quickly under the great numbers and battle prowess of the Yuan forces.
The Eastern Route Army arrives at Hakata Bay on June 21, and decides to proceed with the invasion without waiting for the larger Southern force which has still not left China.
They ae a short distance to the north and east of where their force had landed in 1274, and ware in fact beyond the walls and defenses constructed by the Japanese.
The samurai respond quickly, assaulting the invaders with waves of defenders, denying them the beachhead.
At night, small boats carry small bands of samurai into the Yuan fleet in the bay.
Under cover of darkness they board enemy ships, kill as many as they can, and withdraw before dawn.
This harassing tactic leads the Yuan forces to retreat to Tsushima, where they wait for their Southern Route Army.
However, over the course of the next several weeks, three thousand men are killed in close quarters combat in the hot weather.
Yuan forces never gain a beachhead.
The first of the Southern force ships arrives on July 16, and by August 12 the two fleets are ready to attack Japan.
On August 15, a major tempest strikes the Tsushima Straits, lasting two full days and destroying most of the Yuan fleet.
Contemporary Japanese accounts indicate that over four thousand ships were destroyed in the storm; eighty percent of the Yuan soldiers either drowned or were killed by samurai on the beaches.