Ninjutsu is largely considered the bread and butter, so to speak, of a ninja's jutsu library. Unlike Taijutsu's internal use of chakra or Genjutsu's external use of chakra for illusions, Ninjutsu is an external use of chakra that physically affects the world around it. For the most part, Ninjutsu is not a subtle art or requires much creativity like its illusion counterpart, and brute force can be a plus with ninjutsu, depending on the level of the jutsu being used.
Defining Ninjutsu
Ninjutsu is the external use of chakra, via jutsu, to physically alter the world around it without the use of tools or illusions. All ninjutsu involves the use of Shape and Nature manipulation to various extents. If the jutsu is an illusion, it is Genjutsu. If it affects the user's body internally, it is likely a Taijutsu technique.
Types of Ninjutsu
Elemental Jutsu
Elemental jutsu are named as such because the chakra used is manipulated to form an element as part of the jutsu. The only element jutsu considered as elemental jutsu are those of the Katon (Fire), Raiton (Lightning), Fuuton (Wind), Suiton (Water), and Doton (Earth) types.
Low level jutsu, those of D-rank to C-rank and some B-rank, are designed so that hand seals are used to perform the nature manipulation. Jutsu of B-rank and higher exclude those seals, requiring the user to perform the nature manipulation themselves. An user cannot perform nature manipulation for an element they lack affinity for. E-rank elemental jutsu either do not exist or are extremely rare to find.
Non-Elemental Jutsu
A catch-all category, non-elemental jutsu consists of all ninjutsu that does not fall into the Elemental Jutsu categories. Included in this category are non-elemental jutsu, jutsu performed with elemental combinations, and elemental jutsu outside of the five types listed above.
With true non-elemental jutsu, shape manipulation takes on the same importance as nature manipulation has for elemental jutsu.
Similar Jutsu types
Senjutsu
Senjutsu, also known as Sage arts, are ninjutsu techniques that require Nature chakra. These techniques may be designed explicitly for Senjutsu, or they may be enhanced versions of regular ninjutsu.