Japan helped Subhash Chandra Bose, also known as "Netaji," during World War II because they saw him as a valuable ally in their fight against the British. Japan was at war with the British and the Allies, and they were looking for allies to help them in their fight. Bose, who was a leader of the Indian independence movement, saw an opportunity to gain Japan's support in his own fight against British colonial rule in India. Bose believed that the British were the main obstacle to Indian independence, and he saw Japan as a powerful ally that could help him in his fight against the British. He formed the Indian National Army (INA) with the help of Japanese soldiers and launched an attack on British-controlled India in 1944. Japan saw Bose as a valuable ally, not only because of his leadership of the INA and his potential to weaken the British in India but also because of his ability to mobilize the Indian soldiers in the British Indian army to join the INA, which would have weakened the British war effort. In addition, Japan also saw Bose's INA as a propaganda tool to show the world that they were fighting for the freedom of oppressed people. Bose's INA also served as a tool to win over the support of the Indian population, which would have been useful in the post-war scenario. In summary, Japan helped Subhash Chandra Bose because they saw him as a valuable ally in their fight against the British and his INA as a propaganda tool to win over the support of the Indian population.