Yoo, Young Kuk who is called "the pioneer and monumental being in the Korean abstract line arts," stubbornly and ceaselessly pursues his own world of paintings from the 1930's till today even in the difficult historical situations. His own study us an artist began forms entering the Dept. of Oil Painting of Tokyo Culture Institute in 1936. In received the first prize when he exhibited the work of constructivist relief at the 2nd Liberal Artist Exhibition in 1933, and participated in NEG Fine Arts Exhibition and Independent Exhibition. Through such exhibitions, he made the foundation for study of abstract fine arts. His works show the consistent forms of gametrical abstract based on natural forms from after the Liberator till today, escaping from the constructional inclination at that time of Liberal Artist Exhibition. During all his periods, his theme consciousness, that is, the material Laking a hint from the nature and geometrical forms accomplished high level of art world with his own creative lines, plains and colors according to the changes of his times. The mode of his own paintings is divided into the five periods. The first period(1935~1942) shows a rigid constructivist inclination tried on the basis of liberal thoughts, which enlarges the concept of materials and pursues the order of abstract construction through the removal of colors and the pursuit of forms. The second(l946~1959) slows the deepening of his own inner world through the image, nature and the pursuit of deformed partition based on the configuration of nature and the shape of heavy, soli a plainary construction. In the third(1960~1966), the nature beyond the concrete image, that is, the space or nature is cohered at nature by a strong colored lights. And the construction of color itself in observed with remarkable stress of color planes. The fourth is again divided into two periods: The former period directly shows the arrival of original form of nature through the rigid construction of circle and triangle rather than the space of color plane. In the latter period, the pictures are forming with the rigid construction with cold trigonometric forms of line plane and color. In the fifth(1973~present), concrete image is developed in the them, "mountain" in nature, and the form is repeated. And Planarization of color is accomplished as the refraction of that form is purification.