Final answer:
The Incident of 1942 BS, also known as the Mukden Incident, established the supremacy of the Shumshers in Nepal.
Step-by-step explanation:
The Incident of 1942 BS, which is also known as the Mukden Incident, took place in Shanghai. It was a conflict between Japanese and Chinese troops that resulted in a ceasefire on May 5, 1932. This incident established the supremacy of the Shumshers, who were a prominent family in Nepal. The Shumshers gained power and control over the country as a result of their involvement in this incident.