Where the samurai were keen on facing off one on one with an opponent, even on a battlefield, the ninja were far more practical. They fought to win by any means necessary, and engaged foes in face to face battle in such a way only when no other way was possible.
It is important to remember that fighting was considered something too refined for normal folks, so the samurai made sure that the only people with weapons were nobles and samurai. The regular village and town folk of Japan were at the mercy of those with the swords.
This is where the ninja came in. The ninja did not only use swords in the manner of the samurai, but became expert in using any item as a weapon. Sticks, staves, oars, darts, clubs, grappling hooks, even a weight on a rope or chain; the ninja was proficient in all of these and more. Often, they would take the katana of their fallen foes, or raid a battlefield for good weapons among the dead and build up their own arsenal.
Like all legally disarmed citizens throughout history, the locals found ways to fight back and defend themselves against tyranny, and the ninja quickly became both feared and folk hero to the local populace. They defended their homes in secret, and brought swift and terrible justice to their oppressors – so much so that the daimyo, or War Lords, of ancient Japan soon realized the value of hiring the shinobi, or ninja, for their own espionage purposes. All in all, when it came to wielding the sword, they were deadly beyond belief.