__Team:__ Karasuno High
__Height:__ 179.5 cm
__Year:__ 1st year, class 4
__Number:__ 12
__Position:__ Middle Blocker
Yamaguchi always hangs out with Tsukishima and is very protective of him. He has trained himself hard to use a jump float serve. He is also a substitute ace server of the Karasuno Volleyball team.
