Ninjutsu is known as the art of endurance / perseverance/ patience, the Chinese and Japanese characters for Nin (忍) in Ninjutsu is a combination of 2 other word which is sword (刃) on top of the heart (心). There are a lot of movies or animation out there that brought the art of Ninjutsu to the public like American Ninja, 3 Ninjas, Shinobi, Ninja Turtle and Naruto.
Ninjutsu was traced back all the way to the 14th century feudal Japan with the war during Iga Province and Kōga of Japan, Samurais warriors that fought in the “actual” battle while shinobi are used as Spies, Assassin, and Thief. Ninjutsu is an art that should be taught to a shinobi in the ancient days but in this modern age it is taught to the public. During the ancient times, the male ninjas are known as Shinobi or Ninja where the female ninjas are known as Kunoichi. Although both practice the art of Ninjutsu but the focus is different.
Ancient Shinobi’s training can include techniques of gathering information, techniques of not being detected, avoidance, misdirection, disguise, escape, concealment, archery, medicine, explosives, and poisons.
There is a total if 18 different skills/disciplines that will be taught to a shinobi and it depend on them to choose the skill that they prefer to master.
The 18 Discipline:
1. Seishin-teki kyōkō – A Technique where one refine their mind and soul, Where a practitioner form a mindset to push the body to the limit allowing them to accept pain during training and actual battle.
2. Taijutsu – Unarmed body combat that teaches the practitioner to break / snap bones, striking on weak points of a human body, understanding the posture and how to fall without injuring one’s body, Striking patterns, Throws and Locks.
3. Kenjutsu – The art of sword fighting which is the same technique that Samurai uses. Kenjutsu is also considered as the mother of Kendo.
4. Bojutsu – The art of staff fighting, techniques involve are slashing, swinging, and stabbing with the staff. On Modern day Bojutsu is associated either with kobudō or koryū budō.
5. Shurikenjutsu – The art of throwing shuriken, in traditional Japanese martial arts of throwing shuriken. Shuriken comes in 2 forms, Bo-shuriken which is a straight metal spike which looks like a small iron chopstick but sharp the one that was used by Naruto is a Bo-Shuriken. The other one is a Hira-shuriken, which looks like a flat star with approx of 3mm in thickness and 10 - 12 cm wide.
6. Sōjutsu – Or known as the art of spear, The first design which was brought in from mainland China and was later modified to what it is now.
7. Naginatajutsu – The art of naginata, Naganita looks like a sword attached to a pole / wood staff. This are most seen in battlefield in the Ancient times where mostly used by soldiers and warriors.
8. Kusarigamajutsu – This style of fighting uses weapon is quite unique and it is normally used by Shinobi only The Kusarigama is made up of the Kama, a wooden handle with a curved blade on one end that look like a sickle. The Kusari, a chain attached to the Kama and a small Iron weight on the other end that allows the user to swing the weapon.
9. Kayakujutsu – The art of handling explosion, Sorry as I cant manage to write in more details regarding this as there was not much information.
10. Hensōjutsu – The art of impersonation and it is not like what you see in Ninja Cartoons. Hensōjutsu is an Art of disguise / impersonation where the shinobi will be doing a role-play to avoid being spotted and blend in well with the crowd by appearing as a farmer or priest and ect. Hensōjutsu is a specialized art for kunoichi as the chances of being suspected is lower. And for those who are well trained in this art, it is believed that they can even impersonate others in terms of appearance.
11. Shinobi-iri – The are for stealing and silent movement, this allows the shinobi to enter enemy’s terittory without being spotted
12. Bajutsu – The art of horse back riding and battle on horses.
13. Sui-ren – The are of water, water can be used in many ways, examples are like making boats or rafts and how to control the raft without being spotted, weakening bridges, poisoning water source, hiding in water and finding water in unlikely places.
14. Bōryaku – Tactics / Strategy to assist influence to the opponent.
15. Chōhō – secret information and it was one of the duty of the ninja were spying, it is like the ancient CIA
16. Intonjutsu – The art of escaping, basically Shinobi will be tied up during the training and was expected to escape from it.
17. Tenmon – The art of understanding and using the weather towards the advantage of the Shinobi.
18. Chi-mon – Known as modern day geography to assist the Shinobi’s escape or Sabotage.
I’m not sure on current subjects that the current Ninjutsu schools are teaching at the moment but according to sources, the dojo’s focus towards the practitioner are more towards Taijutsu, Kenjutsu and other armed discipline.