In 1966, after graduating from Tokyo’s Tama Art University with a degree in interior design and doing a few odd jobs, Hidetoshi Nagasawa got on a bike and cycled out of Japan.

He boarded a ship to Thailand and on arrival, resumed his bike expedition across Southeast Asia and the Middle East, sleeping under bridges or trees at night. Fifteen months later, he arrived in Milan where his bicycle was stolen.

Rather than being incensed by the theft, Nagasawa was grateful, for it signaled the end of his journey and the beginning of his art. “Dove Tende Aurora” (“Where The Aurora is Going”) at the National Museum of Art, Osaka, is a retrospective of Italy-based Nagasawa’s conceptual sculptural and installation works from the 1970s through to the present.

Many of Nagasawa’s ideas were generated from his continental cycling, such as the silk canopy enshrouding bronze columns in the grapevine designs of “Viti di Bagdad” (“Vine of Baghdad,” 1975) which is based upon the artist’s impressions of his time spent in Iraq. His earliest works, however, engage similar conceptions to the Japanese Gutai and Mono-ha movements, as well as obliquely engaging the everyday objects of the Arte Povera movement, which came to critical attention in Italy a month after Nagasawa arrived in Milan in 1967.

Other similarities exist, such as Nagasawa’s “Da Interno a Interno” (“Internal to Internal,” 1971) a play upon the interior and exterior parts of a split rock, and Mono-ha artist Nobuo Sekine’s “Phase — Mother Earth,” 1968), a hole dug in the ground from which the dugout dirt was shaped into the positive form of the negative space of the hole and placed in temporal juxtaposition. Further evocative resemblances exist, too, but appear more coincidental than influential, and it is not until the later ’70s that the artist’s more mature style begins to emerge.

Like so many other Japanese artists and designers, Nagasawa’s works are often interpreted as having a Zen aesthetic because of a refined, minimalist feel to the pieces that is often not immediately comprehensible. Nagasawa balks at this description, though he is partly responsible for it, having at times suggested that he obtains his ideas for projects when the world opens up to him during a state of semitrance.

His objection, however, is a pertinent one, because while religion pertains to belief, Nagasawa is interested in ideas. In his garden works, for example, Nagasawa takes no interest in drawing connections to the Zen tradition of the garden as a sacred landscape, but understands his own creations as reflections over space and time that also carry aromas.

The most obvious example of this is “Tempo Zero” (“Time Zero,” 1992) which somewhat resembles a stone garden set inside a golden otherworldly alcove. The stones were originally part of one object, which was sawed in half, a quarter and then two two-eighths — an object divided in space and time. The smell of beeswax that covers the interior walls encourages a flow of the viewer’s own honeyed recollections. As Nagasawa says, an artist must stimulate thoughts and ideas, not beliefs, and these occur to the artist most readily in his ideal trancelike state that he calls “time-zero.”

What Nagasawa means by ideas is a bit Delphic but relates to a comprehension of a primordial world, absent of the concept of linear time. Out of this emerges a general universalism and fundamental principles that govern man and the universe alike. In more artistic terms, ideas are at one with concrete forms, and not separate entities. For example, the two marble cones of “Due Coni” (“Two Cones,” 2002), shapes taken from nature’s mountains, interpenetrate each other to create form that does not occur naturally. Nagasawa elaborates: “Sculpture isn’t the act of making something look like nature; it’s the act of creating another form of nature.”

As in “Due Coni,” where two forms are merged into one, Nagasawa delights in blending dualities such as lightness and weight, the visible and invisible. In “Libellula” (1999), Latin for “dragonfly,” Nagasawa has created a huge fulcrum in iron that seems precariously balanced but whose weight is dissipated by a hovering structural form. Flanking the fulcrum are two folding screens that resemble traditional Japanese lattice shoji paper screens, except rather than evoke an airy lightness of paper, they are made of wax and metal, evincing a thick and heavy feel.

Concerns with the visible and invisible are most clearly borne out in the work giving the exhibition its title, “Dove Tende Aurora: Bosco di Colonne” (“Where The Aurora is Going: Forest of Columns,” 2008). Here viewers enter a large dark room and move toward the columns of trees of the subtitle. Forty nine columns of marble are connected by slabs of marble at the top, arranged geometrically and dimly lit.

As the spectators eyes become accustomed to the dark, the columns fall into faint view and evoke two senses of aurora. The first is the light phenomena at the earth’s poles and their occasional columnar luminosity. The second is to Roman mythology and the goddess of dawn, Aurora. She brings light to darkness and is therefore consonant with intelligence and creativity. While the templelike columns emerge from the darkness, Nagasawa also holds that within the structure, the spirit of the artist resides inside an invisible sphere.

In Nagasawa’s oeuvre there are four other works with the title “Dove Tende Aurora,” and across his output, other titles are repeated at occasional intervals, which connect separate works and compile variations of theme to give continuity. The accretion of verbal nuance and layered meanings lends Nagasawa’s sculptures further attractive conceptual play, and reflection upon these additional ideas lasts long after leaving the physical artworks behind.

“Nagasawa: Dove Tende Aurora” at The National Museum of Art, Osaka, runs till Dec. 13; open 10a.m.-5 p.m. (till 7 p.m. Fri); admission ¥850. For more information, visit www.nmao.go.jp/english/home.html