Iwa-enogu (Mineral Pigment) is the key material Futagawa used in his work. Such paint has been employed in historical Japanese painting which is made from minerals that have been ground into powder form and are to be used with glue to adhere the pigment onto the painting surface. The paint becomes more vivid and dense as the layers build up, creating a sense of depth in the picture. The chroma of Futagawa’s painting seems to be between realistic and dreamlike, like a piece of memory that has coalesced with the artist’s inner being. Futagawa has spent years of practice acquiring the technique of using such material which requires high proficiency especially in delineating the details of a painting. Despite ​​the efforts, mineral pigment presents a unique coloration and glows like a diamond which truly embodies the beauty of the scenery and the artist’s love for nature.

In recent years, new elements have appeared in Futagawa's paintings. Silhouettes of human figures integrate into his landscape picture as if they are visitors to the natural scenery. They are surrounded by blossoms and greenery and got lost in the wildwood. It is the vastness of nature that reflects the frailty of human beings. Human beings should stay awed and humble towards nature. Futagawa published a series of works centered upon such motifs while he traveled to the prefectures within Japan to further research their history through historical site visits, and painted the scenery that captures his experience. His painting resembles a double exposure in film photography. It records this ever-changing scenery while depicting one’s inner peace. Futagawa's works present a sense of surrealism that exceeds traditional Japanese paintings. He has constructed a new form of realistic painting. The artist wishes one could appreciate the magnificent landscapes in Japan and the beauty of mineral pigment.