Musso (1897, in Kediri, East Java – Madiun, in 31 October 1948) was one of PKI leaders and one of figures in Madiun affair.
Musso was born Munawar Musso in 1897, Pegu, Kediri. His father was a bank clerk in Wates, Mas Martoredjo.
In Batavia, Musso studied at teacher school. He met Alimin, disciple of G.A.J. Hazeu and D. van Hinloopen Labberton. According to Soemarsono, one of PKI leaders in Madiun affair, Musso continued to Hogere Burger School in 1913. Musso stayed at Tjokroaminoto's boarding house with Alimin and Sukarno. According to Arnold C. Brackman, at the time Musso worked as cashier at Surabaya post office. In Surabaya, Musso also met Henk Sneevliet.
Musso and Alimin had more important task in infiltrating Sarekat Islam than Surjopranoto. They were members of both PKI and SI before they were arrested due to Afdeling B affair. Musso involved in farmer revolt in Cimareme, Garut supported by Sarekat Islam Afdeling B. In the trial, while Alimin confessed the false statement he made to help Tjokroaminoto, Musso didn't do the confession. In the prison, Dutch government handled him poorly. Agus Salim complained to Voolksraad for this treatment. According to McVey, Musso held a grudge to Dutch government after this treatment. After Musso and Alimin were released in 1923, the former was offered to teach Indonesian language with English as language of instruction in Japan by van Hinloopen Labberton. However Japanese government rejected Musso reasoning he didn't have sufficient academic diploma, though McVey assumed the main reasons were his experience in prison and his political view. Musso then reorganize Batavia PKI branch and led the new one.
In January 1925, committee of Indies National Congress conducted a meeting resulting the neutral, Surabaya-based association Indonesian Study Club. There was presence of Musso at the club first convention in February supporting the club agenda and wishing it to be closer to grassroots. Also in early 1925, Musso and Alimin gave speech in a rally organized by VTSP in Banten increasing communism influence there. After the failure of machinists' strike on 5 October, Musso concluded that the strike was too early than expected.
In December 1925, PKI leaders planned to rebel to the Dutch Indies government. The government knew this and arrested most of the leaders in January 1926. Musso was one of who managed to escape. He along with Budisutjitro and Sugono fled to Singapore meeting PKI agent Subakat and Alimin who previously staying with Tan Malaka in Manila. The five plus Sardjono, Mohammad Sanusi, and Winanta discussed for three days concluding the execution of revolt middle of the year. The meeting also resulted sending Alimin to Manila to request Tan Malaka to support the idea which was rejected. In February, another meeting was held but Alimin didn't mention the rejection by Tan Malaka.