Born 1967 in Miyazaki prefecture (Japan), based in Tokyo.

Since graduating from the Department of Painting at Musashino Art University, he has worked as a manga artist, debuting in book form with New Engineering in 2004. Yokoyama's choice of a manga format rather than traditional 'tableaux' stems from his need to draw the flow of time in association with human actions and things moving or being transformed. Calling his manga works "neo-Manga," Yokoyama typically depicts expressionless characters wearing distinctive fashion, doing things for reasons that are unclear, against a background of near-future scenes that oddly fuse natural and artificial objects. There is virtually no dialogue, but the narrative proceeds at a rapid pace from frame to frame, making heavy use of onomatopoeic sound effects and lines drawn to represent motion. This is a completely new style of manga, and has been highly rated worldwide. In parallel with his worldwide publications in book form, including Travel (2006) and Baby Boom (2009) he has been the subject of a solo exhibition "All Documentation on Neo Manga: I'm Drawing the Time" (2010) at Kawasaki City Museum, and has participated in exhibitions at many art museums and galleries.