Jack Yung Chang

[1] Among their teachers was Li Dazhao, one of the founders of Chinese Communist Party and a friend of Zhang Shizhao.

In the spring of 1930, he took the national matriculation examination for foreigners in Berlin and was ranked second out of three thousand candidates from over ten countries.

He entered University of Göttingen to study mathematics, and he also took classes in physics, chemistry, philosophy and Latin.

[4] In the summer of 1936, due to financial troubles, Chang returned to China and taught at National Shantung University.

Chang held tightly in his arms a 1607 edition of the book Jihe Yuanben, Chinese translation of Euclid's Elements, which he had borrowed from Yu Ta-wei [zh].

He visited the École française d'Extrême-Orient and discovered a number of ancient Vietnamese mathematics books written in literary Chinese, so he looked around and bought some copies of them and also some historical documents.

[3] The hot climate, harsh living condition and frequent Japanese airstrikes at Yishan aggravated his sickness.

In December the same year, he became critically sick, and on his mother's request he was discharged from hospital and was carried back to his home in Kowloon.