In Surakarta (Solo), batik traders formed Sarekat Dagang Islam (SDI) to strengthen indigenous Muslim merchants facing intense competition in the batik trade. The organization began mainly as an economic association, but it created a ready-made network that could later be mobilized for politics.
In the early 1910s, SDI’s membership and ambitions grew beyond a small local trade group. As branches spread, the organization increasingly linked economic problems to wider social grievances under Dutch colonial rule.
After a period of tension and a brief colonial suspension, SDI was renamed Sarekat Islam (SI) in Surabaya. Dropping “trade” from the name signaled a broader mission and helped SI present itself as a mass organization, not only a merchants’ union.
SI’s first major congress in Surabaya drew very large crowds and strengthened coordination between branches. The meeting also elevated H.O.S. Tjokroaminoto as a central leader, helping SI become one of the most visible anti-colonial mass movements in the Indies.
The Indies Social Democratic Association (ISDV), a socialist organization, began influencing parts of SI—especially in Semarang—by working through labor activism and political education. This created a lasting internal tension between SI’s Islamic-nationalist leadership and a growing left wing.
By the mid-1910s, SI reported dozens of branches across the archipelago and hundreds of thousands of members. Its religious identity helped it organize widely, making SI the first nationalist political force in Indonesia to gain truly mass popular support.
Debates over Indie Weerbaar (a proposed Indies defense force during World War I) intensified conflict inside SI. Disagreements over cooperation with colonial authorities, labor politics, and strategy helped the left wing gain influence in some branches while the central leadership struggled to keep unity.
SI leaders, including Tjokroaminoto, joined the Volksraad, a colonial advisory council with limited power. Participation reflected a strategy of pressing for change through constitutional channels, even as other activists criticized the Volksraad as too weak to deliver real self-government.
In 1920, Indonesian communists organized as Perserikatan Komunis di Hindia (PKH) (a predecessor of the PKI). Communist organizers still worked through SI networks in some areas, raising fears among SI’s Islamic leaders that the movement was being pulled toward international communism.
At SI’s 1921 national congress, leaders pushed a rule against dual membership in other political parties. The decision forced many communist-aligned members to leave, formalizing the split between “white” (Islamic-nationalist) and “red” (left) currents and weakening SI’s unity.
Dutch authorities jailed Tjokroaminoto in 1921 on a perjury charge, removing SI’s most prominent figure from day-to-day leadership. His imprisonment showed that even “constitutional” nationalist leaders could face repression when colonial officials saw them as politically threatening.
After Tjokroaminoto’s release in 1922, SI’s central leaders tried to reassert control over branches and unify the organization’s direction. The goal was to restore discipline after years of factional conflict and to limit further communist influence.
At a congress in Madiun, SI reorganized more explicitly as a political party (often described as Partai Sarekat Islam). This marked a shift from a broad association toward a more disciplined party structure—partly as a response to the earlier split and growing colonial surveillance.
After the split, left-wing activists built their own organizations, including groups described as Sarekat Islam Merah and later Sarekat Rakjat, to support communist politics. This reorganization meant SI no longer served as the main umbrella for competing ideologies, reducing its reach as a mass coalition.
Major anti-colonial revolts associated with the communist movement erupted in 1926–1927 and were crushed by Dutch forces. The aftermath brought mass arrests, exile, and tighter restrictions on political life—an environment that also narrowed SI’s room to organize and campaign openly.
By 1927, SI had lost much of the momentum it held in the 1910s: the 1921 split reduced its coalition, and the post-1926 crackdown hardened colonial controls over politics. SI’s legacy, however, endured—its mass organizing helped shape later Indonesian nationalism and trained many future leaders in modern political mobilization.
Sarekat Islam: growth, politics, and suppression (1905–1927)