The effects of teaching of Wasan geometry by the use of Van Hiele Geometric Thinking Levels on the learning of preservice teachers

Wasan geometry (as flourished in Edo period in Japan) includes complex geometric problems. Van Hiele geometric thinking levels were in order and they include educational instruction ways. By this study, we proposed that Van Hiele levels and geometric success levels will increase by the proper instruction of Wasan geometry. The subjects of the study were 60 preservice teachers from a public university primary education department. Three data instruments were used: Van Hiele test developed by Usiskin and two parallel achievement tests on the topics of tangents of circles, similar triangles, and Pythagorean Theorem. After 2 weeks of intervention, pre and post test results were compared and analyzed. In the intervention group, there was a slight increase in the achievement scores but in the control group, there was a decline. Van Hiele results showed decrease both in the groups. By the chi-square tests, there was significant increase in the number of the preservice teachers with low Van Hiele levels. Between day instruction and evening instruction classes, with respect to the posttests of two groups (experimental and control), there found to be significant difference. Increase in the achievement of intervention group was identified as low. Then day classes (1st education) and evening classes (2nd education) students were compared. We realized that groups were not equally distributed. In short, Wasan geometry had a possible effect on success of the students.