Hiramatsu studied under Kazuo Sakata. Although he is recognized as a pioneer of abstract painting, he remains an obscurity in the overall art history of Japan. He was born in Okayama, then lived in Paris from 1921 when he was 32 yeas old, and exhibited his works in the Salon de Thuy Lurie annually. He was fascinated with the cubism of those days, so entered Leger's Research Institute where he gradually became recognized. While he was in Academy Modem, and Leger became ill he rose to become a Leger assistant and lectured to students who gathered from all over the world. Another assistant was Ozenfant.
Sakata exhibited two works in "The Art Exhibition of Today (Art d 'Aujourd' Hue)" which was Paris' first worldwide avant-garde art exhibition in l925. Then he became a world-esteemed avant-garde artist.
In this exhibition, 88 artists from 20 or more countries, mainly Europe and the United States, exhibited 241 works. Masters of modern art such as Arp, Brancusi, Delaunay, Ernst, Miro, Mohory-nagy, Mondrian, Ozenfant, Picasso, and Leger also participated. "The Art Exhibition of Today" was an epoch-making event which symbolized an emergence from feudal society and the arrival of a free life along with the development of contemporary industries. The showing of works at this exhibition was considered to be a sign of belonging to a social movement and as active participation in social reform.
Although many Japanese artists lived in Paris those days, only Sakata from the oriental world participated in this exhibition, so later he enjoyed world recognition as an avant-garde artist. Sakata's works of his younger years in Paris resemble Leger's in style due to his position as Leger's assistant. However, after he returned to Japan, his style gradually became his own form of abstract painting, and became a peculiar expression of Eastern world calmness.

The representational painting expresses the object as it is seen, while the abstract painting expresses its invisible content, heart, and consciousness.
Cubism was a stage of transition toward the contemporary art which would sweep the art world of the postwar period.
Artists who espoused both cubism and abstract painting were few in the world. Considering such aspects, Sakata is an important figure in modern art history. The new beauty of modern times is based on life-changing instruction to those who seek individuality and originality. His appeals against "authoritarianism", "commercialism", and "academicism'' earned him rebuffs from the painting circles of Japan.
Although Sakata came back to Japan only shortly before World War II, that Sakata's statements concerning the avant-garde were considered heretical in a conservative region like Okayama. It was a quite a contrast when Tsuguharu Fujita returned to Japan, soon to produce art in cooperation with the army.
Eventually the former founded the first Avant-Garde-Okayama (A-G-O) of the postwar period in 1949, and held 4 exhibitions. In Japan, the term avant-garde is synonymous with "leading edge" and the acronym "AGO".
The avant-garde art which Sakata strove toward, would be a new and unique one that did not imitate the existing arts. Its instruction would be the opposite of conventional imitative instruction. He never invited a visitor into his studio. Furthermore he prohibited his students from displaying fine-art magazines which might feature other artists' work in his studio. He also demanded his students "throw away the picture they did yesterday and do a new picture today."
Hiramatsu got to know Sakata when he returned to Okayama, she decided to study with him, and converted her style to abstract painting. She participated in all A-G-O exhibitions.
More than 150 letters between Hiramatsu and Sakata from that short period exist as important records. He praised in his letter Teruko's work exhibited in the A-G-O exhibition as being the most excellent and distinguished. He wrote in a letter two years before he passed away, "My life may soon end, so please take my baton and try hard." It was his will that she succeed his avant-garde spirit. Sakata's inevitable end came in l956 at the age of 67. Since he opposed the authority of the central art circles, he was overlooked by the contemporary art historians of Japan as being another local artist.
A letter from Tadao Ogura (a curator of the National Museum of Modern Art, Kyoto) to Hiramatsu in the postwar period described her as his true student succeeding his spirit unlike any other student of Sakata" (after evaluating Sakata's development from cubism to orientalist expressionism). Then he concluded that the main stream of Japanese art was victim to colonialism. "The western world absorbs Japanese and other oriental styles, obtains inspiration and creates original work. On the other hand, Japanese artists are slaves to western trends. They lack the consciousness and effort to draw from their most familiar Japanese traditions or to modify them." Mr. Ogura supported Hiramatsu's innovation toward Japanese traditional cultures and their modernization.
Hiramatsu reemerged in Tokyo and worked as a fine arts teacher after the war. She held an exhibition of her works there.
She was discovered by Shuzo Takiguchi, poet and prewar avant-garde educational campaigner. So she got an opportunity to open her own private exhibition at the Takemiya Gallery, which promoted the latest fine arts.