For example, the time and place of an appointment could be written on the screen and filed into a calendar, said Makoto Araki, a Sony spokesman. The computer would file the appointment into the proper place in the user's schedule, which could then be called up for review.

With a 16-bit processor and 320 kilobytes of built-in RAM memory, the computer is said to be capable of recognizing English letters and more than 3,500 complex Japanese characters - in more than one million variations of individual writing styles.

The computer uses "fuzzy logic" - a set of reasoning rules that enables a computer to process information expressed in vague and imprecise terms. ''Fuzzy logic" has been used in other Japanese computers to imitate human reactions for functions that require flexible responses, such as starting and stopping subway trains.

"A keyboard is still faster and will continue to be used by many people," Araki said. "But for those who have not learned how to type, the PalmTop will be useful."

The PalmTop will be available in Japan beginning April 1 at a cost of $1,320, Araki said, and Sony eventually hopes to offer a version for export.