What is Hanshinkan Modernism, as in Koiso Ryohei and Yoshihara Jiro: Dividing Ridge of the Hanshinkan Modernism, the exhibition on view until May 27 at the Hyogo Prefectural Museum of Art? Hanshinkan is the area extending from Osaka to Kobe, characterized by a long, narrow strip of land between the Rokko mountains and the sea. Kobe and environs have historically been internationally minded, and from the Meiji Restoration (1868) until World War II, the area developed along new interurban train lines as a pleasant residential district fusing Western and Japanese architectural traditions. The show's title references the Hanshinkan Modernism exhibition held at this museum and others nearby around 20 years ago in the wake of the 1995 Hanshin-Awaji earthquake, framing the region's ongoing reconstruction in the hopeful light of its forward-looking roots. Both of the featured artists were from the area, and this retrospective highlights what they shared in common as modernists at heart as well as contemporaries and Hanshinkan compatriots, along with their more noticeable differences.

Ryohei Koiso (1903-1988) was an art-world insider, studying at the prestigious Tokyo School of Fine Arts, showing in prewar Imperial exhibitions, studying in Europe, dispatched to the front to paint official War Record Paintings, and known today as a master of the Yoga genre (Japanese Western-style painting, as opposed to Nihonga, modern Japanese-style painting). Jiro Yoshihara (1905-1972) came from an affluent family that ran a cooking-oil company, but did not follow a conventional academic art path. He was largely without formal art education, avidly followed the latest overseas art developments, constantly pushed boundaries, and is remembered today as leader of the seminal postwar avant-garde Gutai group.

At first glance, the oblique three-dimensional latticework of the Sunny Hills cake shop has the delicacy of a transparent veil. Upon observing the full-scale mock-up, however, one understands that the interlocking wood joinery actually provides a rigid shell structure strong enough to support a three-story building. Through this lattice, Kuma fully exploits the materiality of wood through jigoku-gumi, or "hell-joinery." Ironically he is able to spotlight the fundamental properties of wood material and Japanese traditional joinery by showing it to us in this novel weaving process.

And similarities? For one, they both started out in the context of Yoga. Koiso was a consummate draftsman whose early paintings are marked by loose, confident brushwork, keen empathy for their subjects, and rich, dense blacks, used to ravishing effect in objects, like the sewing machine in Needlewoman (1932), and shadows. In the portrait His Repose, a prominently displayed book or poster reading "MANET" pays tribute to perhaps his most obvious influence, along with Degas. Not that Koiso seems derivative -- his best prewar work stands up today as some of the boldest and freshest Yoga.

Yoshihara's earliest work is lighter in palette and more sparing with paint, and already shows playful discombobulations and a taste for the bizarre, as in his spooky doll still lifes. By the 1930s he was impatient to experiment more daringly, and among the most charming things in this show are his clever forays into Surrealism and abstraction while following the letter of the militarist government's proscription on both: Man Wrapped in Rope, a helmeted diver with an armful of coils and a hose, and other people amid jumbled objects look like Surrealist nightmares, while titles like Landscape are given to works that appear abstract, until you make out a road or tree. One assumes he refrained from publicly exhibiting outright abstractions like Work 3 (1934).

Like many successful painters, Koiso was recruited to document the war, and these paintings are a fascinating if sometimes disturbing part of the show, his always deft strokes rendering subjects like Desperate Charge of Lieutenant Kurata that we can imagine were not his favorite sort. The four trips to the front may have left him sapped (he later spoke of regrets for helping fan the war fervor with his art), as his postwar paintings seem a bit tighter and fussier. Later, though, as an admired teacher at his alma mater (now called Tokyo University of the Arts), his style continued to evolve, and his late portraits and landscapes regain an appealingly limber vitality.

In the postmodern (or post-postmodern) present, Modernism has become a chapter of art history. In Japanese art and architecture, the modern era roughly corresponds to the Taisho (1912-1926) and Showa (1926-1989) eras, when Yoshihara and Koiso were active, and its zenith was the postwar economic boom period of 1954-1973. These two decades were when Yoshihara arrived at a mature style after decades of restless experimentation, and became a mentor to younger Hanshinkan artists as leader of the Gutai group. He urged artists to "Do what no one has done before," and the members explored materials and surfaces, action painting, performances and happenings -- breaking new ground at the time, and decades later gaining renewed critical acclaim that continues to this day.

Meanwhile, after a lifetime of working in styles including Surrealism, geometric and biomorphic abstraction, Art Informel (the French counterpart to Abstract Expressionism) and avant-garde calligraphy, Yoshihara began producing large, simple and powerful abstractions, particularly his best-known series of Zen-inspired circle paintings. Majestic and meditative, no two alike, these and an enormous, striking untitled blue and red triptych at the exhibition's end convey an artist at peace, the circle of his long and varied career complete.

By the time we reach the last section of the exhibition, any ostensible similarities between the works of Yoshihara and Koiso are long gone. Yet setting aside regional and historical context, and whatever else unites or divides the two artists, this is a well-paced and rewarding show that covers huge stylistic distances with many intriguing highlights along the way.