Ozawa with his wife received a grant to travel to Europe (England, Austria, Italy, Switzerland and France) and United States in 1927, collaborating with the Massachusetts researcher Joseph Augustine Cushman. During that period and after return to Japan Ozawa performed mostly foraminifera research, both gathering his own samples and analyzing samples of other researchers.
Five months after his return in Japan, Ozawa contracted typhoid fever and died 29 December 1929.[2]
Afterward, the Geological Society of Japan [ja] established "The Geological Society of Japan Ozawa Yoshiaki Award" which is granted to young (under 37 years old) scientists for exceptional contribution to the field of geology.[3][4]
Ozawa Y., "The post-Paleozoic and late-Mesozoic earth-movements in the inner zone of Japan", Koto Commemoration volume 1925
Ozawa Yoshiaki, "On the classification of Fusulinidae", Journal of the College of Science, Imperial University of Tokyo, vol. 45, art. 4, pp. 1–26
Ozawa Yoshiaki, "Paleontological and Stratigraphical Studies on the Permo-Carboniferous Limestone of Nagato", Part 2. Paleontology. Journal of the College of Science, Imperial University of Tokyo. vol. 45 art.6 pp. 1–90[5]
Ozawa Y., "A new genus, Depratella, and its relation to Endothyra", Contributions from the Cushman Laboratory for Foraminiferal Research vol. 4, part 1, pp. 9–10, March 1928
Ozawa Y. et al., "An outline of a revision of the poly-mophinidae", Contributions from the Cushman Laboratory for Foraminiferal Research vol. 4, part 1, pp. 13–20, March 1928
(full bibliography of 'Ozawa Yoshiaki comprise at least 45 publications)
