The BIA's attempts at establishing a government during the invasion led to it being dissolved by the Japanese and the smaller Burma Defence Army (BDA) formed in its place.

As part of the Anti-Fascist People's Freedom League, the BNA was re-labelled the Patriotic Burmese Forces (PBF) during a joint Allied–Burmese victory parade in Rangoon on 23 June 1945.

[4] At the same time, thousands of Indian labourers migrated to Burma and, because of their willingness to work for less money, quickly displaced Burmese farmers, who instead began to take part in crime.

The former monk Hsaya San sparked a rebellion by mobilising peasants in rural Burma after protests against taxes and British disrespect towards Buddhism.

[8] The Burmese colonial army under British rule included only minorities such as the Karen, Chin and Kachin and isolated the majority Bamar population.

Colonel Keiji Suzuki, a staff officer at the Imperial General Headquarters in Japan, was given the task of devising a strategy for dealing with Southeast Asia and he produced a plan for clandestine operations in Burma.

The top Japanese agent in the country was Naval Reservist Kokubu Shozo, who had been resident there for several years and had contacts with most of the anti-British political groups.

After discussions at the Imperial General Headquarters, it was decided in February 1941 to form an organisation named Minami Kikan, which was to support Burmese resistance groups and to close the Burma Road to China.

In pursuing those goals, it would recruit potential independence fighters in Burma and train them in Japans ally Thailand or Japanese occupied China.

[19][20] The BIA formed was broken into six units which were assigned to participate in the invasion of Burma in January 1942, initially as intelligence-gatherers, saboteurs and foragers.

The leader of the Burma Independence Army were declared with Keiji Suzuki as Commander-in-Chief, with Aung San as Senior Staff Officer.

[26] Throughout the invasion, the swelling numbers of the BIA were involved in attacks on minority populations (particularly the Karens) and preyed on Indian refugees fleeing from the Japanese.

The worst atrocities against the Karens in the Irrawaddy Delta south of Rangoon cannot however be attributed to dacoits or unorganised recruits, but rather the actions of a subset of regular BIA and their Japanese officers.

Eventually the British and Indian force broke free and continued their retreat, having lost ten tanks, two field guns and 350 men killed or wounded.

As the invasion speedily continued in Japan's favour, more and more territory fell into Japanese hands who disregarded the agreement for Burma's independence.

[31] As the BIA's ranks had swelled with thousands of unorganised army and volunteers, with plenty of weapons spread throughout the country which led to widespread chaos, looting and killings were common.

[32] However, the BIA's attempts at creating a government were dared by Colonel Suzuki, who said to U Nu that:[22][35]"Independence is not the kind of thing you can get by begging for it from other people.

[39][40] After a year of occupation, on 1 August 1943, the newly created State of Burma was granted nominal independence by Japan and became a member of the Greater East Asia Co-Prosperity Sphere.

The Imperial Japanese Army maintained a large presence and continued to act arbitrarily, despite Japan no longer having official control over Burma.

As the British General in the Burma Campaign William Slim put it: "It was not long before Aung San found that what he meant by independence had little relation to what the Japanese were prepared to give—that he had exchanged an old master for an infinitely more tyrannical new one.

Force 136 was also able to make contacts with members of the BNA's Karen unit in Rangoon through agents dropped by parachute into the Karenni State, the Karen-populated area in the east of Burma.

In contrast to Force 136, Civil Affair officers of Lord Mountbatten in the South East Asia Command (SEAC) wanted him tried for war crimes,[42] including a 1942 murder case in which he had personally executed a civilian, the Headman of Thebyugone village, in front of a large crowd.

General William Slim later wrote: "I would accept [Aung San's] help and that of his army only on the clear understanding that it implied no recognition of any provisional government.

Aung San and others subsequently began negotiations with Mountbatten and officially joined the Allies as the Patriotic Burmese Forces (PBF) in 23 June 1945.

At the first meeting, the AFO represented itself to the British as the provisional government of Burma with Thakin Soe as Chairman and Aung San as a member of its ruling committee.

Negotiations then began with the British over the disarming of the AFO, which earlier in March the same year had been transformed into a united front comprising the Patriotic Burmese Forces, the Communists and the Socialists, and renamed the Anti-Fascist People's Freedom League (AFPFL).

Had the British Governor of Burma, Reginald Dorman-Smith, still in exile in Simla, and General William Slim gotten their way, the BNA would have been declared illegal and dissolved.

However, Supreme Allied Commander Louis Mountbatten was anxious to avoid a civil war and to secure the cooperation of Aung San, who had authority over thousands of highly politicised troops.

[2] When the British noticed with alarm that PBF troops were withholding weapons, ready to go underground, tense negotiations in a conference in Kandy, Ceylon, were held in September 1945.

[25][2] Aung San was offered the rank of Deputy Inspector General of the Burma Army, but which he declined upon the return of Governor Dorman-Smith's government.