September 1274 – After Korean officials encouraged
Kublai Khan – head of the Mongol
Yuan Dynasty – in 1267 that Japan would be easily subdued, the Koryo Korean state built over 300 large ships to aid an invasion of Japan. With over 20,000 Mongol troops as well as 5,000 Korean, the allied armies departed Masan on board 900 ships on 15 September 1274 in
a failed campaign to conquer Japan.
May 1899 – The port of Masan was opened with pressure from Japan. Among the initial trading goods were salt, fish, cotton and other goods.
15 March 1960 – A protest against electoral corruption was spearheaded by the
Democratic Party in Masan. Approximately 1000 residents attended the demonstration, which took place at 19:30 in front of the Democratic Party Headquarters in Masan. The protest sparked violent clashes between demonstrators and police officers in which seven students were killed and some fifty others injured. To restore order, authorities blacked out Masan and General
Carter B. Magruder eventually dispatched US Marines to quell the unrest.
11 April 1960 – The body of Kim Ju-yul was discovered in Masan Harbor. Kim – still dressed in his uniform from Masan Commercial High School – had disappeared in the March 15 clashes.
October 16–20, 1979 –
Protests broke out in Masan (as well as in Busan) against the regime of President
Park Chung Hee following a brutal police crackdown on a sit-in strike of female textile workers from YH Trading Company. Workers in Masan's Free-export Zone even managed to create four labour unions. ==Administrative divisions==