More than a half-century after the United States shattered Japan's war machine and will, then rebuilt the country on a Western model, Japan's ethos can still seem elusive and inaccessible. From the U.S. heartland, Japan often appears filled with contradictions: a modern nation with an archaic monarchy; tiny islands with a global economy; home to ancient temples and sophisticated businesses equally adept at making high-performance automobiles and giddy cartoons.

Tetsumi Kudo is an unlikely guide to the mysteries of Japan's post-World War II character. An avant-gardist who achieved notoriety in Europe and Japan during the 1960s and '70s, he died in 1990 and is remembered primarily for experimental paintings, sculpture and performances dominated by dismembered body parts, fake flowers and slimy things in Day-Glo bird cages. Essentially unknown in the United States, Kudo is the subject of a new retrospective at Walker Art Center that not only illuminates his career but also offers insight into the contradictions of his homeland. The show's themes are often somber, but Kudo's playful touch lifts the mood.

Smartly organized by Walker curator Doryun Chong, the show is Kudo's first major museum retrospective in the United States, and its lively, well-illustrated catalogue (Walker, $40) is the first extensive publication about him and his work in any Western language.

Born in Osaka in 1935, Kudo was a child during the war and relatively protected from its devastation. Afterward he studied art at the University of Tokyo and moved with his wife to Europe in 1962. The couple lived there, primarily in Paris, for the next 25 years, though they returned to Japan periodically to visit family and participate in exhibitions. From 1987 to 1990 he was a professor at his alma mater in Tokyo. He was just 55 when he died of cancer in 1990.

Kudo's art is metaphorically laced with all the big troubles that afflicted his homeland in the second half of the 20th century -- the horrors of the war, the socio-political traumas of defeat, the environmental degradation caused by rapacious industrialization, the spiritual alienation of individuals adrift in a world bereft of god(s). His surrealistic sculptures of fetus-like dolls stuffed into bottles, and mournful papier-mâché faces and hands in bird cages, are obvious metaphors for the existential malaise of the postwar years. His blasted landscapes of mutilated flowers festooned with dismembered body parts -- bruised arms, bloodied feet, lost hands -- echo the war's devastation. Likewise, his incongruously pretty scroll paintings in lilac, pink and lime, imprinted with ghostly hand and foot prints, recall the bomb-etched shadows of people who were vaporized in the nuclear explosions at Hiroshima and Nagasaki.

Heavy stuff.

And yet there also is something whimsical and upbeat about this expansive, well-focused exhibit. Kudo clearly tapped into the bleak zeitgeist of his time, but he also tuned in on the zany vibes that made the '60s so memorable. Hence the hot pinks, canary yellows, lime greens and electric blues that give a jaunty air to even his most surrealistic vignettes. He had a lot of fun with noses -- turning them into a line of bright yellow "birds" perched in a blue cage, and transforming them into slug-like leaves clinging to the stem of a fake rose.

There are penises everywhere, sometimes emblematic of Japan's post-war impotence, and other times morphing into chrysalises that herald new life in a transformed state. The Walker has reassembled a 1961-62 installation that brought Kudo his first notoriety in Japan, a room in which hundreds of soft, blackened, penis-shaped objects dangle from the walls and overhead lattice like raccoon-tail trophies. Called "Philosophy of Impotence, or Distribution Map of Impotence and the Appearance of Protective Domes at the Points of Saturation," it was a shockeroo in Tokyo at the time but seems a little campy now, a premature relic of the '60s sexual revolution. In its day, however, Japan was reexamining its identity in the postwar world, students there were protesting government corruption, U.S. troops still occupied the island of Okinawa, and a youth-quake culture was buffeting traditional mores. The limp penises -- and a cascade of international news clips erupting from some of them -- dramatized Japan's "impotence" on the world stage.

Despite the political overtones of such early work, Kudo was not an agitprop artist intent on reforming the system or guilting viewers. Much of his work has an introspective innocence about it, and some of his smaller sculptures and drawings seem more like psychedelic party favors than big-time art. A walk-in blue box in the second gallery is a stoner's paradise filled with bird-cage sculptures and Alice-in-Wonderland flowers -- gigantic neon-hued blossoms illuminated by black light. Cool and very trippy.

His 1968 sculpture "Homage to the Young Generation" consists of a huge, peanut-shaped chrysalis in a pink baby carriage that sports a jaunty pink umbrella and a shopping bag from Monoprix, a popular Parisian department store. There's a brain-shaped blob attached by a pink leash. The exhibit's curator said that originally, the "brain" was motorized and remote-controlled so it could scoot along beside the carriage, moving with seeming independence as Kudo pushed the apparatus around Paris.

"There was a sense of drama and spectacle" in his art, Chong said recently. "He believed that what humans are doing to nature wasn't one-sided, that nature was taking revenge on human activity too. Our pollution is changing us. He did not believe in a return to Eden; there could be no return to purity. Instead, he thought that we have created this condition and we will have to live with it."

Like the homeland he left behind, Kudo was full of contradictions, a somber critic of human frailty and failure and yet a bemused modernist who gleefully embraced the gaudy flotsam of contemporary life.

Mary Abbe • 612-673-4431