Koichi is a popular Japanese given name, derived from the characters "光" (ko) meaning light and "一" (ichi) meaning one. It has been traditionally used for boys but can also be used for girls in some cases. In Japan, Koichi is often written using the hiragana or katakana scripts as こいち or コイチ respectively. The name has gained international recognition due to its usage by notable figures such as Japanese actor and singer Koichi Yamadera, and musician Koichi Nakamura from the band Southern All Stars.
The name Koichi experienced a peak in popularity during the years 1918 to 1921, with a high of 16 births in 1921. However, it gradually declined afterwards, reaching as low as 5 births in both 1994 and 2007. Overall, there were 145 births bearing the name Koichi from 1914 to 2007.