Satsujinken & Katsujinken, an important concept in some old Koryu sword schools (eg Shinkage Ryu and Katori Shinto Ryu).
Satsujinken is ”the life taking sword” and Katsujinken is ”the life giving sword”.
This concept symbolizes an ethical principle: one sword used to kill with, can also be used to save or give life, to protect the weak.
This concept would serve as a guiding principle, with the aim of preventing situations from being resolved solely by lethal force. One would not draw one’s sword without some caution. In a confrontation, could one prevent evil by sparing his counterpart’s life ?