What Is Forbidden Jutsu : Forbidden techniques (禁術, kinjutsu), on the other hand, fall into one of the six main ranks, but are an exception because they are forbidden to learn or perform.

What if forbidden jutsu's are not that strong but let's say they are jutsus of no element like snakes,shadow clones etc but a little bit stronger,not s rank or something,just a rank and you get no choice,you can learn and master senjutsu if you want and find forbidden jutsu's but you can only learn.