Bunkeido, a publishing company in Japan, issued the first teaching material for tokkatsu, “School Life is Fun (Tanoshi gakko seikatsu)” for 1st to 6th grade.
http://www.bunkei.co.jp/school/tokubetu/gakko.html (in Japanese)
This page is taken from the teaching material on tokkatsu.
School Life is Fun (Tanoshi gakko seikatsu) 6th-grade teaching material. Tokyo: Bunkeido