George Koshi attended Japanese school in his hometown near Denver, Colorado, as well as in Kumamoto, Japan. His father decided to send all the children back to Japan when Koshi was five years old. He stayed in Japan for 10 years. When Koshi returned to the United States, he had to relearn English. Partly based on his father's experiences translating and interpreting in legal matters for the Issei community, Koshi decided to attend law school and did so on a merit scholarship from the University of Denver. Upon graduating in 1940, he became the first and only licensed Nisei attorney in the state. In March 1942 he was drafted into the military and later transferred to the Military Intelligence Service Language School (MISLS) at Camp Savage. Out of 12 children in the family, five including Koshi served in the U.S. military.
<br><br>After the six-month language course, Koshi stayed at MISLS to teach one session. Subsequently, he was sent to the War Department in Washington, D.C. At the time of Japan's surrender, Koshi was part of the Pacific Military Intelligence Research Section (PACMIRS) stationed in Camp Ritchie, Maryland. 
<br><br>He became heavily involved in the writing of the new Japanese constitution as a member of the Legal Section at General Headquarters SCAP. Being the only American who could speak Japanese, Koshi was approached by several committees working on the constitution for advice and consultation.
<br><br>He also became a member of a team of defense attorneys during the war crimes trials. He and other American attorneys, along with Japanese lawyers appointed by Japanese government, worked together to gather information and present the defense. Though the trials were based on the American trial methods, Koshi saw very few American witnesses actually take the stand for cross-examination. Instead, the judges typically were presented with piles of statements made by former American POWs and took these affidavits at face value. 
<br><br>Koshi stayed in Japan through the Occupation years, working as a language analyst and advisor to the attorneys. In June of 1974, he returned to the United States and continued his career as an attorney.
<br><br>For his work during the war crimes trials and in connection with the reformation of the Japanese judicial system, Koshi received awards from the Japanese government: "Whatever assignment, whatever work I did, I did my best."
