How is each saiyan transformation/form achieved?


So now , depending how you count them and which sources you count, there are
among 10-20 transformations/forms can attain. (counting Oozaru, non exclusive
saiyan forms, etc.) Which saiyans transformations are the result of rage ,
which are the result of training and which are the result of something else?




# Transformations

  * Super Saiyan: Any Saiyan with a sufficient amount of S-Cells and increase their battle power, they gain more S-Cells. Once the Saiyan attains enough S-Cells, a feeling of strong anger or sadness can trigger the Super Saiyan transformation. After the transformation is attained once, they can transform into it any time by focusing their energy into their back to make it tingle. Saiyans with a very high amount of S-Cells can do the transformation without requiring a trigger.
  

  * Super Saiyan 2: There are multiple ways to attain this transformation. Firstly, a Saiyan must be strong enough to generate a lot more energy compared to the Super Saiyan form. The first way to attain this transformation is when the Saiyan experiences a powerful emotional upheaval, much like the Super Saiyan transformation, but to a greater extent. The second way is through harsh training. The third way is out of instinct from a desperate need such as when someone's life is at stake. Finally, the fourth method is for the Saiyan to feel out the tingly feeling in their back. The power output emitted by this form is greatly increased.
  

  * Super Saiyan 3: This form is obtained generally after harsh training and usually under out of the norm circumstances. Goku was able to achieve this form while he was dead and training in the other world. Goten and Trunks managed to achieve it only during fusion. It's basically a transformation that increases the amount of ki utilised.
  

 **Important Fact** : Akira Toriyama stated in the Saikyō Jump's June 2014
Interview that the SSJ2 and SSJ3 transformations are nothing more than powered
up variants of the SSJ transformation. Hence you could potentially surpass the
power of SSJ3 or SSJ2 while using the SSJ transformation by either training or
through rage like in the case of Future Trunks and Vegeta. Although Trunks's
Transformation is referred to as Super Saiyan Rage or Super Saiyan anger, it's
basically a powered up variation of SSJ2 which was caused because of rage.

Hence to answer your question, there isn't necessarily a regular Super Saiyan
transformation which can only be attained by either rage alone or training, it
can be attained in both ways.  
  
However, the Super Saiyan God transformation can only be attained via the
ritual and not by anger. (Based of the manga), training vigorously with a
Deity and practicing extensive Ki control could also help you attain this
transformation as we see Vegeta use the same against Goku Black in the Manga.
The Super Saiyan Blue, on the other hand, can also only be attained by
training vigorously and absorbing the ki of a god and then transforming into a
Super Saiyan. Super Saiyan Rose is basically the Super Saiyan Blue
transformation when done by an actual deity (Zamasu). Apart from the God
transformation, all the regular Super Saiyan transformations can be attained
through training, rage or even when you are in a life or death situation.
Based on the recent episode, we see Vegeta reach a level beyond Super Saiyan
Blue without actual training but while feeling a strong urge to protect
someone(Keep up his promise made to Cabba), which could be compared to Gohan
attaining the SSJ2 transformation when Cell the Baby Cells were beating up the
Z fighters. So if you possess God ki and can use the transformations,
attaining a level beyond through rage and emotion like the Super Saiyan
transformations seems plausible.

Source: dragonball.wikia.com

