Kenjutsu is one of the 18 disciplines of ninjutsu, as carried down through the generations. Developed for the samurai class, it encompasses all forms of Japanese swordsmanship, including kendo, iaido, and pre-Meiji Era techniques. Kenjutsu varied between schools, but was always about how to use a sword, and in fact means “technique of the sword”. The oldest known schools with a direct lineage to kenjutsu include the Kage-ryu and Chujo-ryu, dating back to the Muromachi Period (c. 1336).
Kenjutsu can be divided into two styles: itto-ryu and nitoryu (one-sword and two-sword styles). The two-sword style known as nitojutsu paired a katana with a wakizashi (a long and short sword). Perhaps the most famous teacher of nitojutsu was Miyamoto Musashi, who founded the Hyoho Niten Ichi-Ryu school. While Musashi did not create nitojutsu, and the form is not exclusive to Musashi’s teachings, his school still promotes the two-sword style today.
To be a master of kenjutsu, a practitioner must be adept in several basic sword techniques. Feigning, cutting, jabbing, thrusting, parrying, footwork, weapon choice, and opponent’s weapon are all crucial elements to excelling at kenjutsu. Feigning is essential for cutting, jabbing, thrusting, and is itself dependent on proper footwork and choice of weapon. By expertly acquiring these basics, a student can use one or two swords, and if he or she is successful enough with two, then the student becomes strong enough to control what Musashi called the “gate” (the space between opponents where all attacks must pass). Only then will one truly be a master of kenjutsu, and one step closer to being a ninjutsu master, as well.
Leonardo is exceptionally skilled in kenjutsu. Despite being trained in ninjutsu by Splinter (and therefore arguably all 18 disciplines), Leo focused on this one aspect, learning it inside and out to the point where he became a prized student of nitojutsu. He never used the katana-wakizashi pair, and instead opted for two katana. Breaking tradition in that way ultimately helps him in battle, however, because the added length of a second katana can prevent attackers from ever getting in close enough where a wakizashi would be more effective.
The nature of nitojutsu also explains much of Leonardo’s personality. Because of the dedicated training to basic movements required for simply acquiring the skills of one-sword style kenjutsu, it no doubt takes an individual at the absolute peak of physical and mental acuity, giving an entire life to rigid practice, to become a two-sword specialist. Leonardo proves that to be true. So the question becomes did his personality allow him to master nitojutsu, or did mastering nitojutsu create his personality? The answer may never be known, but Leonardo is a product of his character and his skills, and that combination makes him an excellent martial artist, and strong warrior.
One of the immediate defining characteristics of the Teenage Mutant Ninja Turtles was that each was practiced in a different weapon. There was no overlap, and there was never any information presented that suggested any of them could effectively handle the weapon of any other. This was certainly not a problem, and added an element of creativity to the characters, but it was never made clear that there was a legitimate reason why this was the case. Each turtle excelled in a different discipline of ninjutsu, as was evidenced by their weapons. But it does stand to reason that before any one of them can become a true master, he will have to learn all the skills, including those practiced by his brothers.
Kenjutsu is just one of the many abilities needed for ninjutsu, but it requires a certain dedication that not every student will possess. Leonardo, however, was meant for this particular aspect of the art, and has proven time and again that his training makes him stronger than many advanced swordsmen. As he continues to develop his skills, there is no doubt that Leonardo will become an absolute master of kenjutsu master, and one day a true ninjutsu master as well.