Following the Japanese invasion of Manchuria in 1931, Ishigaki became outspoken in protesting the Japanese military aggression in China, and reported on Japan for the left-wing magazine "The New Masses". Her articles emphasized the negative impact of imperialism and industrialism on Japanese workers, particularly women. During this time, she adopted the pseudonym Haru Matsui, to protect her family in Japan from possible retaliation for her activism. In the spring of 1937, she moved to Los Angeles, where she contributed a biweekly column to the Japanese American newspaper "Rafu Shimpo", writing under the pen name May Tanaka. This column focused on daily life, while incorporating feminist and antiwar commentary. She returned to New York later that year. In 1938, she went on a lecture tour with the modern dancer and left-wing militant Si-Lan Chen. During one of her lectures, she was invited to write a book by a representative of the progressive publishers Modern Age Books.