Marshal Zhu De (right) talks to Lindsay in Zhu's headquarters in late September 1939.
Radio expert
The surprise attack on Pearl Harbor in December 1941, which led to the United States declaring war on Japan, meant Lindsay's face no longer protected him from the occupying army. His "part-time career" as a smuggler at an end, the economist and his new bride (they wed in the summer of that year) left Beijing for the Jinchaji base.
There he became a full-time radio technician for the armed farmers fighting an arduous war for their freedom and their homeland.
"As an amateur radio technician, my grandfather was always able to use limited resources to rebuild wireless setups without complaining about the supply shortage," Lawrence said.
To improve communication with other resistance forces in northern China, Lindsay tinkered with the radio sets at Jinchaji to make them significantly more powerful and reliable, and made them easier to carry around over rough terrain.
Good communications were crucial for sharing intelligence about the enemy's movements and dodging incoming attacks.
Annoyed by the fact that the world - even southern China - knew hardly anything about the active resistance in the north, Lindsay offered his expertise to Yan'an, the Communist Party's central base in Shaanxi province, to boost its communication with the outside.
Thanks to a larger transmitter and a directional aerial that Lindsay built, professor Lu said, the Yan'an-based Xinhua News Agency was able to send reports to decision-makers in Washington.
"Xinhua's radio broadcasts were of interest to Washington," she explained. "It wanted to know more about the Japanese deployment and operations in northern China."
In the meantime, Lindsay also put his scholarly skills to use. He wrote personal notes and took photographs, shared his opinions with overseas contacts, and passed advice and criticism to leaders of the resistance, including Marshal Nie Rongzhen, the top commander at Jinchaji, and Qin Bangxian, the director of Xinhua News Agency.
In his reports to the US and British embassies and outside newspapers, he wrote about what he saw in Jinchaji and Yan'an. He said he believed the rampant atrocities by the Japanese invaders could only motivate more people in northern China to join the communist-led resistance.
Securing success lay not only in the guerrilla's military capabilities, he said, but more important in the ability to mobilize the masses. He predicted that the organized Chinese peasants could claim victory, and called for support from the West.
Many foreign anti-fascist fighters gave their lives to China during the War of Resistance against Japanese Aggression (1937-45), the longest conflict of World War II. Among them was Canadian doctor Norman Bethune, a now legendary name in China, whom Lindsay took a picture of while he performed surgery on a wounded resistance soldier.