The Williamsburg summit of industrialized nations suffered its first public glitch yesterday when the State Department apologized for critical material about Japan included in the White House briefing book for reporters on this weekend's international event.

Charts and text about such matters as Tokyo's restrictions on imports and the "Japanese export surge" were described by a State Department briefer as "inappropriate" and "not in the spirit of Williamsburg." The State Department official said, "We frankly regret the inclusion of those materials."

The briefing book was compiled at the White House and was given to journalists Tuesday. After Japanese reporters wrote articles noting that the economic performance of their country had been treated critically, Japanese Ambassador Yoshio Okawara complained to State.

Undersecretary of State W. Allen Wallis, who has been handling arrangements for the summit meeting, informed Okawara that he was "surprised" to find the offending material in the briefing book, and apologized for its inclusion, according to Japanese Embassy officials.

The material in question is in an 18-page section of economic information. Six pages deal with Japan, the only country given individual treatment. The meeting's other participants are Canada, France, Great Britain, Italy and West Germany.

According to the book, "Japanese imports of manufactures are small by any measure." It continues: "Japan shields its domestic market from foreign competition through an informal interaction of various interest groups." Foreign companies in Japan, the book says, must deal with "an array of restrictions."

On the export side, the book says that "the United States has taken the brunt of the Japanese export surge." It goes on to explain that "Japanese companies are most aggressive in exporting manufactures when domestic demand falters."

U.S. companies often have made such complaints, and U.S. officials have echoed them at times. But a State Department briefing officer yesterday praised the government of Prime Minister Yasuhiro Nakasone, who arrived here last night, for making "substantial progress" in the areas of economics and defense.

Neither White House nor State Department officials would say that the briefing book data were inaccurate. The main point seemed to be that the time was not right for such a picture of U.S.-Japanese economic relations in the anticipatory glow of "the spirit of Williamsburg."