Check out this awesome footage of the Battle of Amami-Oshima, also known as the Spy Ship Incident in the Southwest Sea of Kyushu fought between the Japanese Coast Guard and a North Korean spy vessel.
The Japanese Coast Guard intercepted the vessel because their intentions were unclear. They fired 25 warning shots after order to halt the vessel were ignored.
The confrontation lasted six hours and over 1,000 machine gun rounds were fired from both sides. The North Korean vessel was hit numerous times and eventually sank into the sea.
The encounter was outside of Japanese territorial waters but was inside their exclusive economic zone which extends as far as 200 miles from Japanese lands.