Conversation so far:
what was the name of japan army during second world war
The Imperial Japanese Army was the official ground-based armed force of the Empire of Japan from 1868 to 1945.
how many people were in the japanese imperial army
There were 6,095,000 soldiers in the Japanese Imperial Army in August 1945.
when was the japanese imperial  army active
The Imperial Japanese Army was active from 1868–1945.
who controlled the japanese imperial  army
The Japanese Imperial Army was controlled by the Imperial Japanese Army General Staff Office and the Ministry of the Army, both of which were subordinate to the Emperor of Japan.

Question: was being in the army optional or mandatory
Self-contained rewrite: was being in the japanese imperial army optional or mandatory