Jirinden (6) The long sword corrects injustice. The short sword is thrust into one’s stomach.
「Tōryū moppara kenjutsu to shōsuru wa, shinbu ni shite korosazu wo honshi toshite, motte fusei wo osamuru no yue nari」（Heishū Jirinden Vol.1, Tōryū daisho-tō no okite)
“This school, which solely calls itself kenjutsu and is divine martial skill (Shinbu神武) which has the aim of not killing, is intended to correct injustice.”
While we try out and wear a sword that suits our hand and our strength, the katana is not something that is decided upon by debating the advantages and disadvantages of its length. Originally the sword (剣, ken, tsurugi) was double-edged with one edge facing the opponent and the other facing one’s self. The katana (刀) divides the two edges of the ken into the long and short swords. Accordingly, the long sword is a tool to correct injustice based on orders received from above, while the short sword is used to pierce one’s stomach as an apology for one’s own mistakes.
Neither the long sword or short sword are tools used for the settling one’s own grievances. Those who carry the single edged katana should never forget the meaning of the two-edged sword.