The Indian National Army was a supplementary force to the Imperial Japanese Army in its southern mainland campaign. It was created by the recruitment of Indian prisoners of war who, in the course of service in the armed forces of the British Indian Empire, had been captured by Japanese forces. The idea of Origin of Indian National Army evolved within the Indian independence movement; it was formed with a view to overthrow the British Raj. The Ghadar Party in February 1915 planned to initiate rebellion in the British Indian Army from the Punjab through Bengal to Hong Kong with German assistance. This plan failed after the information was leaked to British Intelligence. The Second World War again revived the plan and thus in the South-east Asian region the concept of the Indian National Army was initiated by the Indian Independence League. INA was started in two phases: firstly formation and subsequent demobilization of Indian National Army under Capt. Mohan Singh Deb and secondly formation of Arzi Hukumat-e-Azad Hind under Subhash Chandra Bose and reformation of the INA as its army. Both these phases received extensive support from the Japanese Government, militarily and politically.

The first phase regarding the Origin of Indian National Army, started with the leadership of Captain Mohan Singh. The first stage consisted of officers and men of the British Indian Army, who surrendered to the Japanese army during the war in Malay, after the surrender of Singapore on the 15th of February, 1942. In this aspect, the Indian Independence League and which was founded by Rash Behari Bose first in Japan, also supported INA. INA was subjected to the concentrated propaganda of the IIL. Major (Later Lt. Gen.) Fujiwama acted as the chief liaison officer between the I.N.A. and the Japanese army.

Two days after the Fall of Singapore, in 17 February 1942, Indian Prisoners-Of-War (POWs), were gathered at Farrer Park and Mohan Singh, a captain in the 1/14th Punjab Regiment in the British Army, announced the formation of an army to free India. The Japanese always supported the creation of such movement which was anti British. Thus, in early March 1942, the Japanese proposed that the INA become the military arm of the IIL, and that Rash Behari Bose lead the movement. This news was formally announced in June 1942 in Bangkok. However, by the later half of 1942, the Indians increasingly felt that the Rash Behari Bose and Japanese betrayed their trust. In December, Mohan Singh and other INA leaders ordered the INA to disband after severe disagreements with the Japanese. Unfortunately, Mohan Singh was consequently arrested by the Japanese and exiled to Pulau Ubin. However, only a few officers were with Mohan Singh. The other armies remained in the I.N.A. and did not want to break the oath of allegiance a second time also felt that the Japanese may vent the fury on the Indian civilians. A Council of Action was formed with Rash Behari Bose as president, Major Gen. Bhonsele as director and other senior officers assisting him.

On the other hand, in 1940, Bose was imprisoned by the British for his anti-colonial activities. During the outbreak of war in Europe, Subhash Chandra Bose saw an opportunity to authorize on Britain`s weakness. In January 1941, Bose went to Russia from Calcutta via Afghanistan and also fled to Germany through Afghanistan by pretending to be a deaf-mute Pathan. On 2 April 1941, Bose reached Berlin, and began advocating India`s Independence through radio broadcasts. He tried to secure support for an armed insurrection in India. For the next six months, Bose and his assistants led an intensive recruiting campaign amongst Indian POWs (prisoners of war).

Subhash Bose entered Southeast Asia in the early days of 1943. In South East Asia with a large population Bose established an anti-colonial force to fight the British. In January 1943, he led the Indian nationalist movement in East Asia as a response of the Japanese. He reached Tokyo on 11 May 1943 and encouraged the Indian communities to join in the fight for India`s Independence. On 2 July 1943, Subhas Chandra Bose reached Singapore. He assumed leadership of Indian National Army in a ceremony held at Cathay Building. He had a vital contribution on the Origin of Indian National Army. Under the able leadership of Bose, the demoralized attitude of the INA changed. INA became doubled in strength as local civilians joined. Many Indians joined and they were from the barristers to plantation workers background. Further, Netaji ensured a well trained army and thus established an Officers` Training School for INA officers. Even, 45 youths were also sent to Japan`s Imperial Military Academy for advanced training. The clarion call of the INA was "Jai Hind" (Victory to India) and "Give me blood and I will give you freedom".

After the Origin of Indian National Army, it received recognition among the Japanese and Indian civilian also supported it. At the end of July 1942, three hundred volunteers were issued with German Army Uniforms bearing a badge on right arm showing a leaping tiger superimposed on Indian tricolour, surrounded by the legend "Freies Indien". The men were then officially designated the "Free Indian Legion". In May 1943, the Indian Legion was moved to garrison duties on the Dutch North Sea coast where they were mainly used for the construction of coastal defenses. After this, they started moving to France. Following the Allied Landings at Normandy, and the rapid advance, the Indian Legion was moved back to Germany in August 1944. Japanese Army assigned in advising the Indian Army, were officers Hideo Iwakuro and Major-General Isoda.

With the origin of the Indian National Army, Bose took the charge of it. He promised the people that he would open second war of independence and set up a Provisional Government of Free India. The Indians of South-East Asia would fight the enemy under this banner. On 8 August 1943, Netaji Subhash Chandra Bose assumed office as the Supreme Commander of Azad Hind Fauj. A Provisional government of Azad Hind Fauj was set up on October 21, 1943. The government of Azad Hind had its own currency, court and civil code, and its existence gave a greater legitimacy to the independence struggle against the British. However, while it possessed all the nominal requisites of a legitimate government, it lacked large and definite areas of sovereign territory. Nevertheless, the government assumed control of the Andaman and Nicobar Islands from Japan in 1943 and the occupation of parts of Manipur and Nagaland. Throughout its existence, it remained heavily dependent on Japanese support. Women Regiment also formed an important part of the Indian National Army.

The main aim of the Indian National Army was freedom of India and the emancipation of its citizens from obscurantist and feudal ideas. "Delhi Chalo" was the slogan Netaji gave his men and began to raise funds and enlarge his army even putting together the women unit. In May 1942, Burma fell to Japanese army. British were afraid that Japanese aided by Indian National Army would invade India from the east. Bose`s slogan - Dilli Chalo (Let us go to Delhi) - had struck fear in the hearts of British. However, regrettably the INA came to an end within a short period but its contribution to the independence of India is unforgettable.