Isbat Session: A Brief History and Mechanism

The Isbat session is an official forum organised by the Indonesian government to determine the start of months in the Hijriah calendar, such as the beginning of Ramadan, Eid al-Fitr, and Eid al-Adha. This session aims to provide certainty for Muslims in carrying out their worship in accordance with Sharia provisions. In its implementation, the Isbat session combines two main methods: hisab and rukyat. The hisab method uses astronomical calculations to determine the moon’s position mathematically, without direct observation. Meanwhile, the rukyat method involves direct observation of the hilal (first crescent moon) on the horizon after sunset. This observation is conducted by experts at various designated locations to ensure hilal visibility. Both methods have strong scientific and religious foundations and have been used in Islamic history. The combination of hisab and rukyat in the Isbat session reflects the government’s efforts to maintain a balance between science and religious teachings. Through this forum, the government seeks to ensure uniformity and certainty in the performance of Muslim worship by combining hisab and rukyat methods and involving various relevant parties. History Since the first year of the establishment of the Ministry of Religious Affairs, President Soekarno’s administration considered religious holidays important, in the context of Muslims being Eid al-Fitr, which needed to be regulated. Therefore, the Government Regulation of 1946 No. 2/Um was born, where its considerations mentioned the need for rules on holidays after hearing from the Working Body of the Central National Committee. Subsequently, the determination of holidays each year is carried out by the Minister of Religious Affairs. On that basis, the Ministry of Religious Affairs of the Republic of Indonesia holds routine Isbat sessions every year. This regulation was signed by President Soekarno on 18 June 1946, has not been revoked, and is even reinforced with other regulations in the present day. When was the first Isbat session held? Notes from M. Fuad Nasar (who now serves as Director of Halal Product Assurance at the Ministry of Religious Affairs) mention the 1950s decade or some sources state 1962, the Isbat Session for determining 1 Ramadan and Eid al-Fitr 1 Shawwal was conducted.