Although only four "lessons" were produced during the series' original run, another two episodes (for episodes 5 and 6) were later produced for the Japan-only Laserdisc collection. They also appear on subsequent DVD releases in Japan and North America. The "New Science Lesson" clips mark the directorial debut of Kazuya Tsurumaki, who went on to direct FLCL, first half of The End of Evangelion and Gunbuster 2. (Source: Wikipedia)