For Women’s History Month, Atlas Obscura delves into the world of espionage, where being overlooked and underestimated has been an asset for centuries of women spies. Read about more of history’s hidden Secret Agent Women. The month before Japanese forces entered Shanghai in summer of 1937 at the start of the Second Sino-Japanese War, Zheng Pingru was featured on the cover of Liángyǒu (translated as The Young Companion for its English edition). The Shanghai-based magazine celebrated the glamorous “modern girl,” the Chinese women who embraced the independence and fashion of…