There is a misconception about the avant-garde artist. It is routinely assumed by the general public that they are fountains of creativity, bristling with ideas and inspiration. A couple of major retrospectives at Tokyo’s Museum of Contemporary Art, however, challenge this view.

One exhibition looks at the work of Atsuko Tanaka, an artist who died in 2005. She was a member of the Gutai Art Association (Gutai Bijutsu Kyokai; literally, “Concrete Art Association”), a Japanese avant-garde group, founded in 1954, which pioneered conceptual and performance art. The other show features the art of Ay-O, an artist whose career also dates back to the 1950s, but who is still very much with us. He was part of the international Fluxus group — which also included the likes of Claes Oldenburg, Christo, and Yoko Ono among its ranks — and spent most of his career in America.

While Ay-O’s show is sure to bedazzle any visitor, Tanaka’s exhibition looks rather dull. This is odd because the Gutai movement was a wildly creative collective that broke away from conventional artistic practice with performance-based art that employed unusual materials. Among their more outlandish expressions were wrestling with mud, throwing paint bottles, and jumping through paper screens.

The exhibition of Tanaka’s art does little to recreate this feeling of artistic anarchy, but the problem seems to be Tanaka herself. Through the exhibition she emerges as a surprisingly timid presence, whose art advanced by small, sequential steps rather than powerful conceptual leaps.

The exhibition begins with works she created in 1953, when she was hospitalized for weak health. These are nothing more than sequences of numbers that have a repetitive, almost autistic quality, and stemmed from Tanaka’s habit of counting down the days to her discharge by circling days on a calendar — a muted echo of a banal act!

Other works rise slightly above this level, such as the prosaically named installation “Work” (1955), which curators have renamed “Bell.” This is a switch connected to a series of bells that ring loudly when pushed. The piece acts like a rather childish form of anti-art. We feel as if the artist is ringing our mental doorbells and then running away, because once the noise subsides there is nothing there.

Her most famous work follows on rather pedantically from this. Entitled “Electric Dress” (1956), it keeps the electronic circuitry, but replaces bells with lights and brings them together into an assemblage that can be worn, rather awkwardly. While the functioning dress must have made an impact at Gutai “happenings,” the exhibition displays an unplugged 1986 reconstruction.

The rest of the exhibition, and indeed Tanaka’s subsequent career, follows on from this work. The plan of the dress’s circuitry apparently mesmerized her to the extent that she started to create sketches depicting it. These later evolved into paintings of colored dots interlinked by lines, which then became paintings of large concentric circles, some of them not without aesthetic impact. However, the image we get of the artist is not one of the mercurial innovativeness we associate with the avant-garde, but of an almost organic process lacking all ambition.

The exhibition of Ay-O’s work, by contrast, is a visual delight. He is popularly known as “The Rainbow Man” because he typically colors his pieces by working through the entire spectrum, sometimes using as many as 192 gradations. But he is just as much an anti-artist, if not more so, than Tanaka.

As a young art student, Tanaka yearned to go to Paris but, as he tells The Japan Times, he was finally attracted to New York because of its association with the abstract expressionist Jackson Pollock and the Surrealist anti-artist Marcel Duchamp, who was then living there.

“I was completely against Japanese ideas and culture like Zen,” he says, explaining his youthful mindset on leaving for New York in 1958. “Because we had lost the war, I thought we should be more Western.”

While admiring Pollock, he also perversely detested abstract expressionism and action painting, which was all the rage in New York when he arrived. His early works, such as “Pastoral” (1956), which he took to America with him, featured faceless mannequins engaged in synchronized actions in a style that seemed ironically cheerful. He had a hard time selling them.

“I took my art to around 150 galleries twice a year for three years,” he recalls. “I couldn’t sell my art, but I became famous as a very funny Japanese Beatnik artist, so people would invite me every night to parties. I didn’t need to (buy anything to) eat myself. But I was not happy. I was always fighting with the New York School people because they would always say art is (having) ‘guts.’ I would say that this kind of guts is what killed Pollock when his car crashed.”

Eventually, Ay-O did the very thing he hated: He created action paintings. Even more infuriatingly they started to sell. But, after a separation of three years, he was finally able to invite his wife over to join him. One of the works he did from this period reflects the conflicts raging within him.

As its name suggests, “Teahouse” (1959-61) is a structure about the size of a small Japanese teahouse. The materials employed in its construction were the boards and panels he used in his action paintings, with holes cut in them and painted black. Its form is a clear reference to the Japanese culture that he reviled at the time, while the materials are a vandalistic recycling of his action painting. In appearance, Ay-O resembles a jovial daruma-san fortune doll, so it is hard to imagine the angry young man who created such a bleakly cynical work.

When he encountered New York artists who greatly admired Japanese culture, however he started to reconsider his attitude. He recalls an encounter with the sculptor Abraham Russell, a fan of Daisetsu Suzuki, the writer who did much to popularize Zen Buddhism in the West.

“I went to his house to interview him for a Japanese art magazine,” Ay-O remembers. “When I arrived there he sat in a chair and said please wait half hour, then he listened to the radio. I asked him what he was doing and he said, ‘I’m listening to a lecture by Daisetsu Suzuki.’ So I asked him, ‘Do you like Zen? Because I hate Zen that’s why I came here.’ “

Soon after this, Ay-O had a profound change of heart. The key moment was discovering John Cage’s famous silent composition “4’33”,” which requires the pianist to hold his hands above the keyboard without playing a note. This work by the Zen-influenced American “anti-composer” had a strong impact on the angry young Japanese painter.

“I suddenly understood everything, and I hated my previous self and became a student of Zen — from America,” he says.

Inspired by Cage’s anti-composition Ay-O started to search for ways to be an artist creating anti-art. In 1964, he stumbled upon the style that would come to define him. Instead of trying to be creative and worrying about the choice of motifs and colors, he decided to use all the colors of the spectrum equally and use motifs that came to him through a wide variety of media.

“My studio was empty because I had a show on,” he remembers of the pivotal day. “I covered the wall with dark canvas, then I painted a color, one color for each day. I did this because I hated painting and was against painting, but I liked to make things, so just a wall was OK. I thought I must use all the colors. If I start painting a visual work it has to have all the colors, I decided.”

But, while creating a method that scorned the whole idea of the artist as the creative source, Ay-O also succeeded in creating art that had a strong visual charm. In this respect he is rare among anti-artists, whose works generally lack aesthetic merit.

The exhibition includes many styles from Ay-O’s long career, but it is the “rainbow paintings” that still impress the most, including “Nashville Skyline” (1971-72), a series of canvases that apply Ay-O’s gradated spectrum to motifs from American folk art.

But doesn’t it bother him that even in his most visually impressive work he isn’t actually being creative in the conventional sense?

“That’s funny,” he smiles warmly. “That’s a very academic idea. No, the art comes, and I just wait and catch it. That’s what John Cage told me with ‘4’33.’ ” I believe him.”

“Atsuko Tanaka” and “Ay-O: Over the Rainbow Once More,” both at the Museum of Contemporary Art, Tokyo, run till May 6; open 10 a.m-6 p.m., closed Mon. www.mot-art-museum.jp.