Kanzenshuu

This is a theory that seeks the answers for:

1. Why SSJ Full Power was stronger for Goku and Gohan in the Cell Games than SSJ Grade 2, and it's still the same thing as SSJ1?

2. Why SSJ Grade 2 became obsolete for Vegeta in Buu arc, and still was such a boost for him in the Androids arc?

3. Why we ...

In my opinion, in the original manga it's implicit that both Tenshinhan and Piccolo learned Kaioken from Kaio-Sama.

In chapter 312 , Tenshinhan says that Goku will win against Freeza because of Kaioken:

https://i.imgur.com/qk9gq7L.jpg

"Don't worry. Goku will win. Have you forgot about Kaioken ...