Motonaga joined the Gutai at the invitation of Jiro Yoshihara in 1955. He attracted attention through a variety of activities such as experimental works and happenings. From around 1958, he attempted a method of pouring paint on the canvas. In 1966, he went to the United States and after staying there for a while, he returned to Japan. He is known for his humorous style characterized by simplified forms and lucid colors.
Entitled Sacred Fire, this painting was submitted to a thematic section by invited artists featuring the Tokyo Olympic Games, which was set up at The 6th Gendai Nihon Bijutsuten. The key colors of the five-ring Olympic emblem, blue, yellow, black (substituted by navy blue), green, and red paint were poured onto a canvas, which was fixed at the top and curved slightly towards the bottom, so that the colors would form layers. Therefore, it is true that there are some coincidental factors, but, on the other hand, the composition including the white circle and the inverted triangle is decided by the artist and by controlling the thickness of the paint or the force with which the paint is poured, how the colors overlap or blur can be adjusted in different ways. Although this painting employs an unconventional method of pouring the paint, its powerful imagery awakens a feeling as if the flame is blazing dynamically before our eyes.