Born in the Imperial Palace in Kobara, Minoru was the second son of then Emperor Itsuki Kobayakawa and Empress Koharu Kobayakawa. Per a practice established by his grandfather, Minoru was enrolled in public schools for his education. During elementary school he attended Kobara Elementary School, Ryumonji Intermediate School and Ryumonji High School. From a young age he took a keen interest in the military, and upon graduating from high school he enlisted in the military and started attending the Imperial Akitian Naval Academy.