In Asia, Charles Lang Freer pursued the precious with a handicap: precious little information.

He did well nevertheless. The museum he founded, the Smithsonian's Freer Gallery, is quite sure of that -- and is celebrating its 60th anniversary with an exhibit that simultaneously shows off some of Freer's most substantial finds in Japan, China, Iran and India, and compares his version of their various origins to what 20th-century scholars now say about them. The differences of opinion shown in "Studies in Connoisseurship, 1923-1983" are considerably less striking than the items themselves.

"Only in the last few years have archeological studies dated these jade pieces from the late neolithic period," says museum director Thomas Lawton, referring to a case of finely polished pieces of Chinese jade, intricately etched with birds, dragons and other symbols. "If I had said this six or seven years ago, people would think I was crazy."

The jade pieces date to 2000 B.C.; Freer believed they were from the Chou dynasty, roughly 1,000 years more recent.

"We still don't know how they did it," says Lawton. "They didn't have metal tools."

Most of the exhibit's other 80-odd pieces aren't nearly so ancient -- including the large "Matsushima" screens by 17th-century Japanese painter Sotatsu, one of only five genuine Sotatsu screen sets known in the world, and the "Khamsa of Nizami," an illustrated folio of Islamic poetry dating to 1548, with its minute, brilliant detail and calligraphy.

They had metal tools then. But you'll still wonder how they did it. STUDIES IN CONNOISSEURSHIP, 1923-1983 -- At the Smithsonian's Freer Gallery of Art through February 29.