Inokuma is best known for his large-scale abstract paintings that allude to industrial landscapes, ladders, rail tracks, derricks, cranes, urban maps, and city planners’ blueprints.

His classmates at the Tokyo School of Fine Arts included Ryōhei Koiso, Takanori Ogisu, Kenzō Okada, Noriyuki Ushijima, and Takeo Yamaguchi.

[4]: 9  At this point, Inokuma had not yet seen the original Young Ladies on the Banks of the Seine (Summer), but he had accurately captured the death-defying languor of Courbet's work, while the Japanese woman's face, hands, and the floral patterns on her kimono were vivid.

[1] However, in 1936, in protest against the reorganization of the Teiten, Inokuma left the organization and formed the New Creation School Association (Shin seisaku-ha kyōkai 新制作派協会; present Shin seisaku kyōkai 新制作協会) with Masayoshi Ise, Ryōhei Koiso, Toshio Nakanishi, Yasushi Santa, Kei Satō, Iwao Uchida, and Kazu Wakita, who, according to their manifesto, shared the "artistic spirit of ‘anti-academicism’".

[5] [6] In November of the same year, the first exhibition of the New Creation School Association was held, in which Takeji Fujishima participated as a special exhibitor in addition to the members' works.

[3]: 7 In 1936, Inokuma also participated in the art competition on the occasion of the Summer Olympics in Berlin, along with other New Creation School Association members including Ise, Koiso, Satō, and Wakita.

In June 1940, Inokuma departed Marseille on the Hakusan-maru, the last Japanese evacuation ship from France, with Tsuguharu Fujita, Takanori Ogisu, Tarō Okamoto and others.

[11] Democracy was installed on the east and west walls of the Student Hall at Keio University's Mita Campus, which was designed by Yoshirō Taniguchi and completed in 1949.

[12] In the early postwar period, money and materials were limited, so instead of using canvas, Inokuma decided to use enamel paint on plywoods screwed together and sprayed with lacquer on the surface.

[13] The two resulting murals depicted young men and women in various poses, singing, playing musical instruments, and relaxing, among animals, in a very lively manner.

[3]: 5  The year after his arrival in the US, Inokuma held his first solo show at the renowned Willard Gallery in New York, where he exhibited abstract paintings such as Haniwa (1956).

[3]: 44 In the late 1960s and 1970s, Inokuma’s color palette became richer, and his style gradually shifted from a bird's-eye view to parallel lines and geometric forms.