This article describes a new method of viewing a historical phenomenon based on its social significance. This method enabled the classification and analysis of a group in a context simultaneously and chronologically. Using historical phenomenology, the authors found a polarisation of Chinese Muslims' thoughts and practices in the Indonesian context. As an example, the technique of classification of Islamic thoughts is illustrated to discover Chinese Muslim figures' religious activities. This method allows an improved social investigation to probe deeply into Chinese (...) Muslims' formal religious life. The evaluation of the effectiveness of the new method is confirmed by the calculation of the polarisation of Chinese Muslim religiousness, leading to the fragmentation and diversification of Indonesian Chinese Muslims in the realms of politics, economic practices or Islamic rituals. New research results improve the understanding of how a social history of an ethnicity could grow and assimilate in a context. The assimilation could contribute to religious harmony in such a pluralistic country such as Indonesia and can be used for making better social decisions, especially related to the lives of minorities, who urgently need policymakers and stakeholders to accommodate the rights of those who are still in the process of gaining fairer recognition. CONTRIBUTION: Using historical phenomenology, this article tries to classify and study a group in a setting concurrently and chronologically. An in-depth social inquiry into the formal religious life of Chinese Muslims discovered a calculation of religious Chinese Muslims' polarisation, which led to the dispersion and diversification of Indonesian Chinese Muslims' politics, economic practices and Islamic rituals. New policy proposals can be made by evaluating religious polarisation. (shrink)