noun
secret swordsmanship; secret fencing traditions
Refers to the hidden or esoteric techniques of a particular school of swordsmanship, often passed down orally or in secret writings.
その流派の秘剣は門外不出とされている。
The secret swordsmanship of that school is said to be kept strictly within the school.
古文書に記された秘剣の技を研究する。
I study the secret fencing techniques recorded in the old documents.