Detail from Slum Wolf by Tadao Tsuge.
Originally associated with controversy, taboo-breaking, and radicalism, gekiga traits have since become subsumed into a wide range of manga, leaving the term gegika with more historical significance today than an overall descriptive function.
— Phillip Brophy, "Osamu Tezuka’s Gekiga: Behind the Mask of Manga"
In 1964, editor Katsuichi Nagai and artist Sanpei Shirato founded a new monthly magazine, Garo, as a "showcase and laboratory for creator-driven manga" (Gravett, 2006, p. 42). Garo (which translates to "art gallery") was envisioned as a place for the work of mangaka that did not conform to the strictures of Japan's mainstream manga industry, similar to R. Crumb's underground comix anthology Zap or Art Spiegelman's glossy art-comic magazine Raw.
Much of the work featured in Garo was part of a style of Japanese comic called gekiga, a "realistic, adult-oriented style, which arose out of anti-establishment manga subculture in the late 1950s" (Kinsella, as quoted in Rosenbaum, 2012, p. 261). Gekiga was "different from the period's mainstream comics titles targeted at kids—less simplistic and fanciful, their settings closer to the street and contemporary reality" (Gravett, 2006, p. 38). While in some quarters the term has become a catchall for any works that are violent, explicit or that simply don't fit into the other broad editorial categories of manga, gekiga most accurately refers to realist Japanese comics from the postwar period that are primarily concerned with "mature" themes such as class, politics and interpersonal relationships. It is also sometimes used to refer to avante-garde or experimental manga from the same period—works that would be included under the catchall category of "alternative manga" today.