We developed the computer calligraphy, that is, a computer formation of brush-written Kanji characters using calligraphic knowledge. The style of brush handwriting depends mainly on the way of using a writing brush. Brush writing skills include the direction of brush at the beginning, curvature and turning the brush, the brush-up at the termination point in a stroke. We make up the calligraphic knowledge base according to the above mentioned brush writing skills. For simulating real brush movement, we represent the brush contact form that is the brush shape on the writing plane as a brush-touch. The system can control the size and direction of this brush-touch during the brush simulation. The system simulates the real brush writing to move the brush-touch along the skeleton letter shape in the standard database. We get the brush written Kanji from the locus of the brush-touch movement. We can extend this system to the new on line training system for brush writing using the simulation of brushtouch movement modified by the pressure, speed and rotation of the writing brush, and the skeleton letters written by a learner from the tablet. This system is also useful for students learning how to write Japanese letters beautifully with brush.

We propose a knowledge-based instruction system for writing beautiful Japanese characters correctly, by using ICAI techniques. With this kind of CAI, it is important to relate the character pattern with the skill knowledge of handwriting because the rules of writing are indirectly shown as a feature of the character pattern. However, the CAI for penmanship previously reported was only based on the pattern analysis of the character. In this paper, we describe the rules of writing for this system as the skill knowledge of penmanship in the declarative way. This system evaluates and reforms the student's handwriting based on the rules of writing stored in a knowledge base. We would also introduce the error knowledge by the student's frequent handwriting mistakes. Finally, this system can estimate the student's degree of handwriting ability by their input charecters and give suitable guidance for improving their skills of writing. Students can learn the skills and the knowledge of penmanship effectively by this system. This system is also useful for foreign students learning the Japanese language.