Koji Yamamoto (?? ??, Yamamoto Koji, born October 25, 1946 in Saeki, Hiroshima) is a former Japanese baseball player and manager of the Hiroshima Carp of Japan's Central League.
A four-time home run king having played for Hiroshima Carp throughout his career, Yamamoto contributed to the team winning five league championships including its first-ever in 1975, and three titles of Japan Series in 1979, 1980 and 1984.
He recorded over 40 home runs for five years in a row from 1977.
With 536 home runs, he is fourth on the NPB career list.
He is known as the Mr.
Red Helmet (???????, Misuta Akaheru), nicknamed after Hiroshima Carp's symbolic red colored helmet.
Yamamoto managed Hiroshima Carp twice, between 1989 and 1993, and later between 2001 and 2005.
He led the team to win Central League championship in 1991.
He was inducted into the Japanese Baseball Hall of Fame in 2008, and is a member of the Meikyukai, or the "Golden Players Club."