Why did the Battle of Inchon or Operation Chromite occur? Because, it was a way for South Korea and the allies to recapture Seoul and to push North Koreans back off South Korea. North Koreans were surrounded by the allied side and had to fight back. Why was South Korea and the allies involved? They started it and it was their plan of attack to as I said above recapture Seoul and to push back North Korea off South Korea. Why was North Korea involved? Because they were surrounded by the South Koreans so of course they were involved! They were either going to die/get captured or fight and die/ get captured...so they fought back. The North Koreans didn't want to lose all the land that they had taken so far.