I have often been asked about the 古典型 (KOTEN-GATA, old classical kata) handed down from my teacher, Asai Tetsuhiko Sensei. So today, rather than explaining in my own words, I thought to share his explanation, verbatim. I'll do that in Japanese first, then translate for all of you who cannot read Japanese. I hope this answers your questions. Osu, André Bertel.
この型は、八方から攻めてくる敵に対し、華麗な回転により、縦横無尽に攻防の技を繰り広げる型である。古典型とは、実践より編み出された攻防の技を合理的に組織体系づけ、構成されたもので、古来より門外不出とされ、伝承されてきた型である。- Asai Tetsuhiko.
"This kata (Hachmon - not stated) is a formal exercise that develops kobo (offensive and defensive techniques) in all directions by splendid (or excellent) rotation against enemies attacking from all directions (literally ‘happo’ — the eight directions, like an asterisk)."
Please note my translation from here...
"The koten-gata (old /classical kata) are formal exercises that have been rationally/systematically organized and composed of kobo (offensive and defensive techniques) devised from practice, and have been handed down secretly (mongaifushutsu) since ancient times".
While this explanation may seem too generic, it really unveils a lot. Furthermore, within IKS we have many Koten-gata which have yet to be taught openly, but contain a lot of knowledge from the past which further enhances the applicability of Shotokan.