Koji is a unisex Japanese given name, derived from the kanji characters 虎 (tora) meaning "tiger" and 時 (jiki) meaning "time". It is pronounced as /ko.dʑi/ in Japanese. The name Koji has been used for both boys and girls in Japan since at least the Meiji period. Some notable individuals with this name include Koji Yakusho, a renowned Japanese actor known internationally for his roles in films like "The Last Samurai" and "Babel", and Koji Tanaka, a celebrated musician who is widely recognized for his work as a jazz pianist and composer.
The name Koji experienced its peak popularity between the years 2016 to 2023, with a significant increase in births from 2019 onwards, reaching an all-time high of 32 births in 2023. Prior to this period, the name's popularity fluctuated greatly, with no clear trend or consistent increase until recently.