A decades-long effort by Indonesia’s second-largest Islamic organization, Muhammadiyah, to establish a globally unified Islamic calendar is gaining renewed attention, despite ongoing debate and resistance. The proposed “Kalender Hijriah Global Tunggal” (KHGT), or Global Single Hijri Calendar, aims to resolve perennial discrepancies in determining the start of key Islamic months like Ramadan and Shawwal, which dictate fasting and Eid celebrations.
The initiative, rooted in astronomical calculations, seeks to replace traditional methods of moon sighting – often subject to regional variations and disputes – with a system based on scientific precision. Muhammadiyah’s current leader, Professor Dr. Haedar Nashir, has repeatedly expressed patience in the face of opposition, stating, “The process may be long, it could seize 10, 50, or 100 years, but Muhammadiyah will patiently wait,” according to an article published by an LPCRPM PP Muhammadiyah member.
The debate echoes a similar struggle faced by Muhammadiyah’s founder, K.H. Ahmad Dahlan, in the early 20th century. Dahlan, after studying in Mecca, discovered inaccuracies in the direction of prayer (Qibla) in Yogyakarta mosques. His attempts to correct the Qibla based on scientific calculations were met with resistance from religious authorities and communities attached to long-held traditions. Some even dismantled a mosque he had realigned, accusing him of introducing innovation and potentially undermining the local Sultanate, according to historical accounts.
Today, nearly all mosques globally utilize the scientifically-determined Qibla direction, a testament to the eventual acceptance of Dahlan’s reforms. Proponents of the KHGT draw parallels to this historical precedent, arguing that scientific accuracy should supersede localized practices in matters of religious observance. The KHGT utilizes astronomical calculations to predetermine the start of Islamic months, offering a consistent and predictable calendar for Muslims worldwide.
Haedar Nashir, who has served as President of the Central Board of Muhammadiyah since 2015 and is a professor of sociology at Universitas Muhammadiyah Yogyakarta, frames the KHGT as a modernization effort aligned with the demands of a globalized world. He argues that a unified calendar is essential for coordinating activities in fields like aviation, finance, and education, which rely on precise timekeeping. He has also authored numerous books on Indonesian politics, religion, and society, including “Indonesia dan Keindonesiaan: Perspektif Sosiologis” (2020).
The KHGT proposal is being analyzed through the lens of leadership theory, specifically transformational leadership and evidence-based problem solving. The initiative, like Dahlan’s Qibla correction, seeks to shift perspectives and integrate scientific knowledge into religious practice. It also exemplifies a commitment to data-driven decision-making, relying on astronomical data rather than subjective observations.
Despite the potential benefits, concerns remain regarding the disruption of traditional practices and the readiness of the broader Muslim community to embrace a global calendar. The debate continues, with Muhammadiyah maintaining its commitment to the KHGT, anticipating that its acceptance will follow a similar trajectory to the eventual adoption of the scientifically-aligned Qibla direction.
