Jutsu Ranks

Most types of techniques are classified under certain and specific ranks. These ranks are determined for each technique how much chakra is used, and how much damage can be done with it. Higher-ranking jutsu usually require high amounts of chakra, causing drain and exhaustion, even threatening the user's life if not used wisely.

E-Class
E-Class jutsu are the most basic types of jutsu. They are taught mostly at the ninja academies to graduates. They are fairly easy to learn, and require very little chakra. An example is the Substitution Jutsu.

D-Class
D-Class jutsu are similar to E-Class jutsu, but require more chakra. They are harder to learn, like the Shadow Clone Technique. Naruto had flunked the test of shadow cloning three times because he couldn't make the clone an exact copy of himself.