The "sword" style of using 9 knives at once to disable and destroy an opponent. While that may sound impossible, the user never actually uses all 9 knives at once except for extreme emergencies, because the concentration needed to do so is incredible.
The actual forms of the style resemble juggling more than anything else, with the user making strikes so fast that the knives appear to be suspended in air, only moving to strike the opponent. In this way, up to 9 knives may be suspended at once, and when this ability has been mastered it seems like time slows down for the user while they must juggle 9 knives at once.
On Dozei Island, unusual sword styles were frowned upon, as efficiency and usability conquered all creativity. However, one small old man who was a juggling master decided once to juggle knives. After years of practice, he got so good at it as to be able to juggle 9 knives at once.
One day, a small boy asked if he could also juggle apples. The old man replied yes, and the boy threw an apple at him. In a flash, the man skewered the apple on one of his knives, and kept juggling. The boy threw a fit, since he hadn't planned on this, but the old man reminded him that he was still technically juggling the knife.
This boggled the boy's mind, and he demanded to know how to do such a thing. The old man took him in as his apprentice, not knowing that the boy only wanted to know how to skewer and slice. After years of practice, the boy grew into a man, and he became immaculate and perfect at this new style of swordsmanship. Opponents scoffed at the man who came into their dojo juggling knives, but were quickly silenced by the speed and misdirection of the style.
One by one, the man went from dojo to dojo, taking their signs and closing them down. Eventually, even this became too easy for the man, and he began a murdering spree, trying to find more talented opponents to face. The military police eventually caught up to him, and hanged him for the murder of over 49 martial artists. When the old man heard of his simple juggling act turned into a tool of murder, he took his own life, slicing his guts with his very own knives.
To this day, the style itself is renowned as a murderer's tool, too sick to be used widely. The small amount of people who do practice it admit they'll never be as good as the first, because they can only teach and learn based on witness' accounts of the murders.
The major strength of the style is both speed and misdirection: Your opponent can't tell what knife is coming next, and the strikes taught in the style are both quick and deadly. However, the style has a very short range ( the length of the user's arms) and the user is easily caught off guard by attacks from the back. However, there are a few special techniques that the style has created.
Hibi no Tsukkakaru (Snake Lunge)Edit
The swordsman briefly stops juggling and roundhouse kicks one of the knives straight into the enemy, putting both more strength and more range into the attack. This is used mostly against opponents who think they know the range of the style, or defend too heavily to be harmed by the small nicks the style normally uses. However, this creates a brief moment where the knives aren't being juggled, so the user must compensate and an opportunity arises.
Saruwa Zengo Tsumugu (Monkey Spins Around)Edit
The swordsman kicks one of his knives over his head, and uses that misdirection to slash at the stomach and neck in every direction. This requires at least 6 knives to be airborne, and is the only technique that can reach the user's back. Striking at 2 different vital points at once creates a big problem for any would-be opponent, but the user must then focus on catching the knife way up in the air, which messes up their rhythm.
Kyu Tsubame Tobikomu (9 Swallow Dive)Edit
At once, the swordsman releases all 9 of his knives, and drives them all at the enemy at once. Only to be used against someone you must kill, this requires both 9 knives out and immense mastery. Not only can the strike be manipulated to change direction at any point by the swordsman, 9 points of contact creates an impossible-to-block strike from the user that will hit each of the enemy's vital points. However, the user must concentrate absolutely on this and any attack aimed at them from somewhere else will surely hit.