He worked in surrealist and abstract expressionist painting styles before turning, in his final years, to the repeated depiction of circles reminiscent of "satori," the enlightenment of Zen. This white circle was made by leaving the canvas unpainted while painting the background black. When asked about his circles, Yoshihara said that he could not manage to paint even one circle with satisfaction, an indication of the depths of his pursuit of this form. Indeed, no two of his circles are shaped exactly alike. (https://en.wikipedia.org/wiki/Jiro_Yoshihara)