Yayoi Kusama left Japan for the U.S. in the late 1950s, and began her radical, era-defining style of art in cities like Seattle and New York City. She was also an activist during the sexual revolution and anti-war movement in the 1960s. In the 1970s, she returned to Japan due to health issues. Compared with the earlier, well-renowned Infinity series and the later Pumpkin series, the Collage series of this period was relatively introverted and mysterious. After her soul mate Joseph Cornell, an artist whom she had been in a relationship with for 10 years, passed away in 1972, Kusama ended her 15-year career in the U.S. and returned to Tokyo in 1973, due to her worsening mental illness. In spite of the conservative atmosphere in the Japanese art sector at the time, she continues to create lots of works and controversial installations. It is exactly the Collage series of this period that require further exploration and rediscovery from art critics.

When Yayoi Kusama returned to Japan in 1973, she left the noisy New York City and the ever-present media behind, disappearing from the public's view. When everything calms down, it was like waking up from a dream to the artist. In 1977, she started to accept mental treatments. The isolation caused her to be gradually forgotten by the mainstream culture and the press. In her studio, Kusama became increasingly bold, with her increased variety in mediums, including collage, sculpture, and even literature. During this period, art was her primary salvation, and she discontinued her earlier, more radical art forms in the U.S., such as installations. She focused on painting and sculpture, and tried many kinds of paintings, where brand-new explorations and trial-and-errors were done.

In the Insomnia Night River was created by Kusama in 1975, it was a summary of her style of breaking the traditional limits, as well as an important turning point in her career as an artist. Being affected by the literature works at the time, her paintings of this period was poetic and extremely narrative. In the Collage series, the elements of polka dots and nets are shown in more implicit ways, and are further covered, resembling a complicated psychological status. The theme includes the thoughts about the start and end of life, which implicitly expressed the illusions that haunted Kusama for her whole life. Every piece of work requires deciphering as a whole, where the soft compositions introduce viewers to the instability in her subconsciousness.

In the Insomnia Night River takes assemblage as its origin, and an abstract art was created on ceramic painted cardboard. Such an art form is similar to flat collage, and can be seen as a three-dimensional expression of collage. In the whole series, flowers, insects, birds and marine animals are the most common themes. This particular piece takes river as its topic, where the artist uses black ink and neon paint to silhouette the direction of the river, and then added dark grey screentones that extends from left to right, causing the misplaced colors to spread like a net, opening up a water channel in the night. The infinitely repetitive polka dots radiates outwards, like the shades from the light of fireflies, and were clipped, pasted and reassembled. The dots under the light resemble the countless sand whirling in the dark river, where the tides give rise to endless criss-crossing networks. They also resemble the countless stars in the night sky, which spans across the sky against the starlight, paving out a miniature universe that extends to infinity. It is the concept of“infinity” and“net” that wove the mysterious rhythm and the fragile yet unrestrained effects, and captured the grand scale and the endless space. Kusama's art always bear her endless desire toward polka dots and an endless world, which can be interpreted as a message of love and peace. She continues to utilize the concepts even today.