Hiramatsu produced these ink works on cloth. Blots and blurs were freely let form in contrast to her controlled Japanese paper works. She returned to Japan in the 1980s to begin to tackle the combination of Japanese paper and sumi.
Works 7, 8
"Door series"
Materials: Japanese paper, sumi.
Minimalist works.
Works  9,10,11
"Original-form series"
Materials: Japanese paper, sumi.
Beauty in which form is emphasized by the sumi technique of black on a white ground.
A further series of black works 7 to l1 focus on the sumi's black on a white ground.
Instead of "miyabi" and the white world being dynamic worlds in the black series, the viewer perceives a world of calm. There is infinite gradation in the black of sumi.
Furthermore, "Snow covered mountain", "a stone and water", "drift ice", "clouds and the moon", "heavenly body", etc. pursue sumi's special features.
These works effectively employ the blotting peculiar to Japanese paper, original techniques were fully employed to replace Hiramatsu's earlier deliberate brushwork styles. As a result, work whose like has never seen before was created; sumi works are not merely black surfaces, but have tones of delicate gradation, which cannot be applied intentionally, as whites and grays can.
Her latest exhibition was held at the Ueda Ware House Gallery, Tokyo, l983. The theme was the Shintoism of Japan with a further degree of abstraction. Groups of big works of up to 240 centimeters square were worthily displayed in the huge warehouse space.
After this exhibition, Hiramatsu got interested in the birthplaces of ancient civilizations and visited many countries of the world. In l987, she traveled to China to visit the ruins of a cave Buddha statue. She created works in sumi and exhibited a cave-Buddha-inspired series in Osaka.
Then she held an exhibition at the huge P3 Art Museum in Tokyo in l990, themed on the ruins of Egypt. Huge works as large as the 10 m by 3 m "Valley of the Kings" were displayed.
Furthermore, she held an exhibition focusing the ancient civilizations of areas such as Greece and Egypt at the Heidelberger Kunstferein Museum in 1995. The hanging-scroll-formatted 2.7 m length Greece group works were hung from the high ceiling and were aligned lengthways in the hall. To experience walking through the exhibition was to experience walking through the ruins of Greece.
Hiramatsu traveled the ruins of the world where monuments used to exist and now desolate scenery replaces once green productive land. Once prosperous civilization obviously fell ruin. Urban culture forgets and destroys nature. Where is a model culture which can continue into the future? Hiramatsu thought that the model must exist in past Japanese culture.
She established "U and a Forum KV" Art Museum in 1990. "U" stands for "universe."