At the end of Yuan Dynasty and in the early of Ming Dynasty, Japanese pirates often harassed Chinese coastal areas, threatening local residence. Local people called these pirates "Wokou". Since the establishment of Ming Dynasty, strict restrictions on Maritime trade and intercourse with foreign countries were carried out. Except for government links with foreign countries, all business over the sea was forbidden. During the middle Ming Dynasty, Wokou sometimes even colluded with Chinese pirates, smuggling arms over sea, plundering and slaughtering. Finally, Ming court resolved to bolster the coastal defenses, and ordered Qi Jiguang to put an end to the pirate menace.

Qi Jiguang (1528 - 1587) was born in Penglai, Shandong province. In 1556, he was assigned to deal with the problem of Japanese pirates in the coastal areas of Zhejiang province. Dismayed at the low morale and the lack of training of the soldiers, Qi decided to raise and train his own army. Soon, he had a force of about 4,000 crack troops. They were known locally as "Qi's army" and soon distinguished themselves.

In 1561, Japanese pirates pretended to invade Fenghua and Ninghai with the real aim of attacking Taizhou. Qi Jiguang saw through the enemy's trick and defeated the invaders at Taizhou. He fought nine battles and won every times. After ridding Zhejiang of the pirate scourge, Qi Jiguang fought Japanese pirates wherever they appeared along Chinese coastal areas. After nearly 10 years of hard fighing, he succeeded in driving the Japanese pirates out from the coastal areas of southeast China by 1565.