Final answer:
The secrecy of Zhabdrung's death was likely due to reasons such as ensuring political stability, smooth transition of power, and cultural practices. The extended concealment helped avoid potential power struggles and maintained the unity established by Zhabdrung in Bhutan.
Step-by-step explanation:
The secrecy surrounding the death of Zhabdrung Ngawang Namgyal, the unifier of Bhutan, and his passing's concealment for over 50 years, can be attributed to several potential reasons. Firstly, maintaining the illusion of his continued presence could have been crucial to preserve political stability and prevent potential power struggles or invasions by external forces. The belief that Zhabdrung was still alive might have deterred both internal and external threats. Secondly, the extended secrecy could have been instrumental in preserving the unity of Bhutan as the delayed revelation allowed for a smoother transition of power and provided time for the consolidation of the political structure he created. Lastly, the secrecy might have been a reflection of cultural practices, influenced perhaps by regional examples of grand burials and elaborate posthumous treatments of leaders that signified power and reverence, as seen in ancient Chinese tombs of the Zhou dynasty.