Yoshio Kodaira was born on 28 January 1905 in
Tochigi,
Tochigi Prefecture to a family of eight as the sixth child and third son, and suffered from
stuttering during his childhood. Kodaira's family ran a merchant's inn. However, Kodaira's father suffered from an addiction to
drinking,
gambling, and
spending, which led to the business going
bankrupt, forcing them to live in
poverty. His paternal family had a history of
mental illness, and all five of his father's siblings suffered from mental illness. During
elementary school, his grades were poor and he was ranked 21st out of 23 students. He also consistently displayed poor behavior; Kodaira's first grade evaluation read "there is no day without a fight" and he was noted as "rude and violent" in his sixth grade evaluation. He was variously described as "careless," "unenthusiastic," "lazy," and "dull." It was also reported that Kodaira would easily become angry when he was unable to communicate his intentions to others. As an adolescent, Kodaira would
bully those weaker than him but was reportedly kind to girls. In 1923, at the age of 18, Kodaira joined the
Imperial Japanese Navy and was assigned to a
marine regiment stationed in
Yokosuka. Early in his military career, he bought the services of
prostitutes in
Yokosuka, and later on indulged in the same behavior in
Australia and
Europe during port calls as a crew member of a warship. According to Kodaira, he sometimes stayed the night with a woman and had sex with her
four or five times. His second wife later remarked how he would demand sex from her almost every night, sometimes twice in one night, despite nearing 40 years of age. However, he was not violent with her. In 1928, Kodaira was stationed in
China and participated in the
Jinan incident where he was assigned to guard the Nisshinbo factory, where he personally killed six
Chinese soldiers by stabbing them with a
bayonet, a feat for which he was awarded the
Order of the Rising Sun, 8th Class. When Kodaira was stationed at
Dagu Subdistrict of
Binhai, Tianjin (the site of the former
Taku Forts), he broke into houses there and raped several women and in at least one instance, ripped open the belly of a
pregnant woman with a sword. == First murder and trial ==