Kubo studied and translated German literature at Tokyo Imperial University and then soon he became the disciple of another famous playwright and theatre director, Kaoru Osanai.

To honor the death of his teacher, Kubo began to write one of his most famous works, which was The Land of Volcanic Ash: A Play in Two Parts, translated by David Goodman.

[4] Shortly after dropping out of high school, Sakae moved back to Hokkaido to practice oil painting and study Japanese literature.

During the course of his college career, he translated over thirty German plays, including works from Frank Wedekind and Gerhart Hauptmann[5] After joining the literary department of the Tsukiji Little Theatre in March 1926, he met Kaoru Osanai, the founder of this new theater.

Without reducing them to stereotypes and without vulgarization, we clarify them in therms of the typical form of conflict and formulate them with artistry and style" [6] After Kubo had finally finished writing The Land of Volcanic Ash, the government had found this play to be problematic, for it showed highly accurate detail of the agricultural conditions of Hokkaido in the mid 1930s.

[2] This play takes place in Hokkaido from late 1935 to the autumn of 1936 in the city of Obihiro and also the village of Otofuke and describes the life of an agricultural community.

There wasn't a valid reason for his anxiety attacks, but it was noted that he felt unyielding pressure for becoming both a successful writer and fulfilling his father's dream of becoming a scientist.