Sha-pen (abbreviation of sharp pencil) is what the Japanese call their mechanical pencils. The word sharp pencil comes from the name the first Japanese maker gave to their mechanical pencil – Ever Ready Sharp Pencil, which in turn comes from America’s trademark name Eversharp Pencil.
The Japanese students like to take notes with their sha-pen even in high school and universities. The teachers and professors generally give tests with questions from the notes so the students like to keep their notes as neat as possible without any unsightly white correction fluid for studying later on. The Japanese students also copy down word to word to what their teacher write on the blackboard. The only time the students use pen in their notes is when their teacher writes with a different color chalk to emphasize certain points.
Even in the most important exams such as university entrance exams, the students write with sha-pen as well. This shows how much the students and the teachers trust each other – the teachers, for trusting their students to not erase and rewrite their answers to claim more marks afterwards. And the students, for trusting their teachers to not to pull any hanky-panky on their papers out of prejudice.