Because i said so U_U
Why does all my trainers need to know what this is? Who's teaching really ~_~
Alucard closed his eyes for a sec..
"A ninja(LOL) opened his eyes and looked at his teacher...
Also known as shinobi is an individual, a fighter who's prepared to sacrifice all for his allied village. They're taught in what we call ninjutsu, which includes the other topics you so needed me to describe ~_~. A ninja utilizes and relies on chakra in their battles, not all but most do(refrains from taijutsu users such as Rock Lee). Each ninja has their own specialties. They can favor a certain element beside the other, some are born with blood-line limits also known as Kekkei Genkai. These are strong combinations of nature elements or hidden abilities such as clan ninjutsu and/or dojutsu such as Byakugan. Or that other emo eye sha..something..
But like i said, a ninja is a "soldier" or intel gatherer, spy. You name it, they get tasks from their ninja leader aka the kage of their village. They do these missions and are most important loyal to their village, some more loyal to their village than their families(wtf).
Chakra(Hm, i didn't think sword-arts relied on this subject that much but oh well)
Chakra is what gives ninja "life" to their abilities, it's the energy that ninjas project into jutsus. It's a spiritual energy that every ninja has but not all can use it. It takes a serious amount of training to project chakra into actual jutsus and even longer to utilize nature transformation that would allow a ninja to transform raw chakra into fire chakra or air chakra. Raw chakra itself can be used in many ways and is the course of Ninjutsu. A ninja can focus their chakra to climb trees by utilizing their chakra in their feet acting like a grip under their feet. A ninja can transform chakra they've gathered into spikes, shields and weapons to use in battle.
Ninjutsu. The utility of chakra, the arts of ninjas and projection of power. This is what ninjas relies on in battle. They gather up their spiritual energy and projects it into ninjutsu. As far as we know, you can also transform your chakra into five individual elements. Fire, rock, air, water and lightning. These can later be combined via bloodline limits or by extremely skilled ninjas who have mastery of the two/three elements of combination. However this is an extremely difficult process and requires time and patience. Two things that not all ninja acquires in their ninja ways >_>.
Taijutsu is another ninja art. It doesn't necessarily rely on chakra and is thus based on physical power. More than spiritual one. That means it doesn't drain the ninjas chakra reserves as much as ninjutsu, but instead it drains stamina. However there's more to taijutsu than just that, you can use it to break genjutsus(which are ninjutsu that paralyzes the opponents body or makes them see illusions by utilizing the chakra from the user into the mind of their opponent). Taijutsu can also help a skilled ninja avoiding eye contact, which is necessary in a fight with certain dojutsu users. Especially those of the mangekyo emo gaze U_U. Taijutsu training also increases the ninjas physique and thus grants speedboosts and close-combat experience. There's also free-form taijutsu that lets ninjas dodging weapons flawlessly or creates dangerous combinations of physical offenses/defenses.
Kenjutsu is the art that i so far lack any training in. It's the art of weapons, mostly swords i assume. The masters of kenjutsu would be the samurai, who completely rely on their kenjutsu in battle instead of ninjutsu/taijutsu. The arts of weapons could be used in many ways since ninja also can carry weapons but lack of kenjutsu training i believe doesn't unlock the weapons full potential and would make the ninja carrying weapons feel like they're carrying a pair of socks instead. I don't know much of these arts, but i am sure that's where you come in mophead >_>.