He had experienced it in Africa where it was a huge success.
The idea of satyagrahas emphasised the power of truth and the need to search for truth.
Gandhi ji believed that satyagrahas could unite all Indians.
He also knew that India can never rival Britain in force of arms as they (the Britishers) were very strong at wars but the millions of Indians can never carry arms and that only non-violent methods could bring freedom in the country.