|Spoiler Alert: This page contains spoilers. Read at your own risk.|
The Great Indochina War, also called the Vietnamese Conflict (大越紛争) , refers to a military conflict that occurred years before the beginning of the story, in which the Great Asian Union tried to conquer the entire Indochina peninsula. 
Course of the War
During the conflict, the South Vietnamese Army waged guerrilla warfare against the Great Asian Union with the help of the then Captain Kazama Harunobu, who ignored the National Defense Force General Command orders to secretly interfere with the Great Asian Union's advance, and openly intervened in the war. With the support of information analyst Saeki Hiromi back at National Defense Force GHQ, Kazama's guerrilla tactics helped in halting the Great Asian Union's advance in time for the USNA and the New Soviet Union to intervene and push back the Great Asian Union. 
While he was hailed as an expert in jungle warfare, for his insubordination, Kazama was shut out of promotion. Saeki, however, was showered with praises, and eventually obtained the rank of Major General, which she would use to promote Kazama to the rank of Major.