“On Kawara: Reading One Million Years (Past and Future)” was installed in Trafalgar Square in London in 2004. (Photo by Marcus Leith/Courtesy David Zwirner, New York/London)

On Kawara, the acclaimed but enigmatic Japanese artist whose body of conceptual works addressed the passage of time in detached, numerical ways, died in New York in late June. He was 81.

His representatives at the David Zwirner Gallery announced his death on its Web site. The artist had lived in New York for five decades. No cause of death was given.

An intensely private man, Mr. Kawara avoided interviews and seldom had his picture taken. He wanted his art to speak for itself, preferring not to attend his own openings and resisting others’ attempts to explain his intentions to the public.

Widely exhibited during his life, Mr. Kawara was featured in shows at major museums and galleries around the world, including at the Museum of Contemporary Art in Los Angeles. The Solomon R. Guggenheim Museum in New York will mount a major show on the artist in February.

Time is the dominant motif in Mr. Kawara’s work, and he explored the subject in diaristic and numerically obsessive ways.

“Today” remains his most famous work — a series of monochromatic paintings that impassively document the dates of their creation. Each painting bears a single date in the language and format of the country where it was created. (The artist made each canvas in a 24-hour period.) His first “date” painting was made Jan. 4, 1966, and the series comprises thousands of individual paintings.

“One Million Years” was one of his most ambitious projects, consisting, in part, of individuals reading a long list of dates spanning 1 million years into the past and the future. The piece has been performed at museums and galleries in the United States and Europe.

Another time-centric piece is “I Got Up,” which documents on postcards the times the artist arose from bed on days between 1968 and 1979.

Critics have tended to categorize Mr. Kawara with such conceptual artists as Joseph Kosuth and Lawrence Weiner, both of whom frequently incorporate text into their creations.

Some also have read Zen and other Buddhistic meanings into his work. Interpretation of his art has remained difficult because of Mr. Kawara’s virtually nonexistent public persona.

A Los Angeles Times review of a 1991 show of Mr. Kawara’s work at the Stuart Regen Gallery in Los Angeles described the artist’s works as “stubborn in their enigma, using but refusing to co-opt whatever information the viewer chooses to bring to them.”

On Kawara was born in 1932 in Japan. As a young man, he moved to Tokyo, where he started exhibiting his work, but his career in his native country was brief. He moved to Mexico City in 1959 and eventually made New York his home.

Mr. Kawara’s first New York show was in 1976 at the Sperone Westwater Fischer Gallery, now called the Sperone Westwater Gallery.

His 1977 solo exhibition at the Otis Art Institute Gallery in Los Angeles was described in a Los Angeles Times review as “strictly impersonal. There is neither confession nor emotion in his work, and aside from mortality, he reveals nothing that the most discreet citizen would choose to keep hidden.”

Though he was press-phobic, Mr. Kawara wasn’t a recluse as far as friends and colleagues were concerned. One of his long-running projects was a series of telegrams sent to associates that bore a single line: “I am still alive.”

Among his biggest U.S. shows were a solo exhibition at the Dallas Museum of Art in 2008 and the year-long “One Thousand Days, One Million Years” at the Dia Center for the Arts in New York in 1993.

The coming Guggenheim exhibition, which was organized with the cooperation of the artist, will be the most expansive U.S. show devoted to Mr. Kawara to date, showcasing works from as far back as 1964 and including a continuous live reading of “One Million Years.”

Another posthumous exhibition is being planned for 2015 at the Museum Dhondt-Dhaenens in Deurle, Belgium.

Although his exhibitions included few biographical details, Mr. Kawara almost always would find a way to mention the number of days he had been alive. For the Otis exhibition in 1977, the catalogue noted that the artist had lived 16,378 days at the opening.

According to his gallery, Mr. Kawara had lived 29,771 days at the time of his death.

— Los Angeles Times