Between 1929 and 1936 Kartosuwiryo was propelled towards the leadership of Sarekat Islam, and they coordinated a radicalization of Islamist politics and non-cooperation. In the aftermath of Tjok- roaminoto’s death, the hijrah policy became a dominant feature of the party’s policies, especially as secular nationalists retreated towards cooperation with the Dutch to achieve self-governance. As De Jonge’s repressive policies cornered Sarekat Islam and Kartosu- wiryo, several long-standing members withdrew their support from the party, eventually leading to Kartosuwiryo’s expulsion.
At the time of the Japanese landing in 1942, Indonesia and the Netherlands had already been rapidly drifting apart. Dai Nippon succeeded in finding its niche in the hearts of most Indonesians, harvesting support in rural and urban areas by co-opting political and administrative agents. The religious movement grew stronger under Japanese rule, as it became more coordinated, created a stronger structure and, most importantly, was provided with an armed wing: in 1948 this would become the core foundation for Kartosuwiryo’s Darul Islam.
While the Allied forces were making progress against the Axis powers, Japan agreed to prepare Indonesia for independence. Japan first supported political Islam as an instrument for deepening its hold on the country’s population, but when the secular nationalist elite was deemed more suitable for the task of laying the foundations of the new state, the Japanese shifted their support accordingly.