With the government partially lifting its two-year import ban on U.S. beef, the fast-food restaurant chain Yoshinoya D&C Co. is preparing to resume its mainstay "gyudon" beef-on-rice dishes next month.

Negotiations with U.S. meatpackers are expected to take no more than two months, and Yoshinoya, once the biggest gyudon chain, hopes to have the popular meal on its menu again as early as January, according to company officials.

The scale of the relaunch, however, will be limited by the amount of beef that can be secured.

Japan slapped an import ban on Canadian and U.S. beef after mad cow disease, formally known as bovine spongiform encephalopathy, was discovered in Canada in May 2003 and in the U.S. in December the same year.

Tokyo removed the ban on the condition that the beef comes from cows younger than 21 months and that brains, spinal cords and other specified risk materials that can transmit the brain-wasting disease be properly removed.

Under those unverifiable conditions, the volume of imports is expected to be only about 5 percent of the volume before the ban.

In contrast, Zensho Co., which runs the Sukiya gyudon restaurant chain, will continue to shun U.S. beef because consumers are still skeptical about its safety.

Supermarket chains are also proceeding with caution.

An Ito-Yokado Co. official said it would closely watch, as "the greatest matter" of concern, how consumers view the safety of American beef.