The towers served to raise alarms against invasions of Japanese pirates.
Historically, they had often used guns and cannons against Japanese pirates as early as the 1390s.
In the 15th and 16th centuries Changshu was several times attacked by Japanese pirates.
In the 16th century they were called upon to rid China's coast of Japanese pirates.
The city wall, parts of which remain to this day, was built in 1554, in order to protect the town from raids by Japanese pirates.
Wielding these swords, the Japanese pirates cut long spears, or even enemy soldiers, into half in a single strike.
The routes of the Korean attack were guided by captured Japanese pirates.
A city wall was built for the first time in 1554 to protect the town from raids by Japanese pirates.
He found out the Japanese pirates had no such problem because they brought onigiri with them.
Wokou or Japanese pirates were one of the key primary concerns, although the maritime ban was not without some control.