Considered a prodigy and with the expectation of becoming a rabbi, Jacob began studying at the Novograd-Volynsky Yeshiva at the age of 12, a school typically attended by much older students.
The Capitulations were canceled and foreign nationals had to choose between obtaining Ottoman citizenship and serving in the Sultan's army or being deported to their home countries.
Towards the end of the 1916 school year, immediately after receiving his Turkish citizenship, he was drafted into the Ottoman army and sent, along with his classmates, to officers training in Constantinople (Istanbul).
As WWI cut off postal services in Europe, Jacob lost contact with his family, Concerned for their safety, he returned to Ukraine at the end of the war to see his parents.
1919 was a year of many pogroms in Ukraine, in addition to the forced conscription of young men into the Ukrainian Nationalist Army which was trying to maintain independence from the Soviet Union.
Fearing conscription, Jacob spent only a short time with his family before moving to Korets then under Polish rule, where he ran a Hebrew school in the summer of 1919.
He decided to study education to establish a cadre of local Hebrew-Zionist teachers in Turkey and to publish Hebrew textbooks that would meet the needs of Turkish Jewry.
[3] There, he devoted himself to teaching and other instructional work in education, organized teachers’ training courses (led by Tzila Greenberg), published textbooks, a Hebrew-Bulgarian dictionary, and reading booklets for children.
Jacob became active in the "Hashomer Hatzair" youth movement and edited their Hebrew weekly publication "Gilayon", where he also contributed numerous articles and short stories.
During these years he started publishing important papers on the teaching of reading and writing in "Hed ha-Hinuch" – the periodical of the teachers’ union in Eretz Israel.