Information and communication technologies have brought great changes in the classroom. A wide variety of multimedia instruction systems are equipped in schools and educational institutions. However, people gradually find pen-paper or blackboard-chalk is still the most natural medium to express thoughts. They are irreplaceable tools for preparing and giving lectures in many subjects such as mathematics, physics and engineering due to their intuitive use and unmatched flexibility. A comprehensive teaching system called Intellichalk was developed based on this idea. Digital ink and information technologies were used to restore and enhance this natural way of expression. The system consists of three parts, a lesson preparation system, a classroom instruction system and a playback player. Each part can be used separately. Lesson preparation system includes a camera with bracket and an independent program. Contents written on the paper can be extracted out digitally and organized as digital ink blocks according to the user’s intention. These descriptive or conceptual digital ink contents can be easily reused to improve the efficiency of lectures. Intellichalk classroom instruction system is inspired by the idea of blackboard. It has a full-featured editor on which users can not only write and draw fluently but also add a wide range of multimedia materials such as images, texts and audios from internet or local disks. Digital ink blocks can be used whenever needed during the lecture. Unlike prepared sliders, this blackboard-like system shows the instructor’s thought process. In order to improve its usability and functionality, three intelligent modules were added to the system: a handwriting recognition module, a hand drawn geometric shapes recognition module and an animation module. Several interesting tools were developed by using these intelligent modules, such as handwriting lambda calculus demonstration program, pen gesture editing assist program and sorting algorithm animation program. The classroom instruction system can be viewed as an electronic blackboard enhanced by multimedia and intelligent technologies. It provides lecturers more possibilities on the form of teaching, gives students chances to follow up the thoughts of the teacher. The highly modular structure ensures that it can be easily configured, extended and upgraded. All the actions on the editor and the instructor’s voice are recorded automatically during the lecture. A player was developed to replay the entire lecture. Compare to normal video records, it has much better graphic quality and smaller file size, which is well suited for long-distance transmission and online playing. The Intellichalk system has been equipped in a multimedia classroom in Free University of Berlin since April 2014. It was configured with a 22-inch graphical tablet and four 60-inch large screens. More than a hundred students and teachers have benefited from the system. Practice has shown that Intellichalk system supports flexible teaching style, enlivens the classroom and provides comprehensive assistance to both teachers and students.