The Existence of Customary and Religious Inheritance Law within the National Civil Law System: A Comparative Study and Codification Prospects

Abstract

Indonesia’s inheritance law is characterized by persistent legal pluralism, operating across three normative systems: customary law (hukum waris adat), Islamic law (faraidh) partly codified in the Compilation of Islamic Law (KHI), and Western civil law codified in Book II of the Civil Code (KUHPerdata). This plurality causes legal uncertainty, gender disparity, and jurisdictional overlaps between religious and general courts. This article examines the interaction of customary and religious inheritance law within the national civil system and evaluates prospects for codification. Using a normative-juridical method with statutory, conceptual, and comparative approaches, it analyzes primary legal materials (legislation and jurisprudence) alongside secondary literature from Sinta- and Scopus-indexed journals. Findings show that while constitutionally accommodated, the three systems remain structurally unresolved, generating persistent uncertainty in mixed-heir and interfaith cases. Comparative analysis indicates that harmonization, rather than rigid unification, provides a realistic reform pathway. Codifying a National Inheritance Law requires a principle-based, optional choice of law framework that preserves customary and religious values while guaranteeing constitutional equality, particularly gender equality. The article concludes that while full codification is sociologically difficult short-term, a harmonized framework anchored in constitutional supremacy is feasible and urgently needed.