Implementation of the MABIMS criteria in determining the beginning of islamic month in Indonesia and Brunei Darussalam

The emergence of criteria made by the Minister of Religion of Brunei, Indonesia, Malaysia and Singapore (MABIMS) in the determination of the beginning of the Islamic month which was the result of the meeting of the Southeast Asian ministers of religion, namely Brunei Darussalam, Indonesia, Malaysia and Singapore which was first held in 1989 in Brunei. The meeting discussed cooperation in the field of hisab ru'yat between the four countries. In Indonesia, the MABIMS criterion is better known as the hisab imkān al-ru'yah method and was discussed for the first time in 1998 in March by hisab and ru'yat experts and representatives of Islamic social organizations - such as Muhammadiyah, NU, Persis, Al- Ershad and others. The deliberation that took place on September 28, 1998 resulted in a decision on 8 criteria for MABIMS in Indonesia. However, in reality the Indonesian government is considered inconsistent with the application of the MABIMS Criteria. According to the initial assumption, Indonesian researchers sometimes prefer the use of rukyat rather than using the MABIMS criteria reckoning. Meanwhile, Brunei Darussalam was impressed with Indonesia when it applied the MABIMS criteria inconsistently, because Brunei Darussalam only applied the MABIMS Criteria reckoning in the determination of the beginning of the Islamic month apart from Ramadan, Shawwal and Dzulhijjah. This research is a normative type of research using a qualitative approach, using primary and secondary data in the study. This research resulted in: First, the two countries only apply in the months other than Ramadan, Syawal and Dzulhijjah, while the determination of the first three months of Islam uses the guidelines of rukyatul hilal. Second, in terms of the validity of the application of the MABIMS Criteria in Indonesia and Brunei Darusslam according to fiqh and astronomy, it is permissible to use the approach of observational data or rukyatul hilal in the field