volitional or not?

[Ira Nanapu]

こんばんは

I just wanna make sure that my concept about volitional verbs in Japanese is correct.
I already know what is volitional or not volitional verbs in Japanese, but what sometimes makes me confuse is there are several verbs that classified as a volitional verb in a theory, but in the other theories, it's classified as not volitional verb.
I give you the examples:

知る 'to know' = volitional or not?

忘れる 'to forget' = volitional or not?

分かる 'to understand' = volitional or not?

I really appreciate your replies. Thanks.
よろしくお願いします
(^_^)

 

[Toritoribe]

忘れる can be volitional. The other two are both non-volitional.

 

[Ira Nanapu]

thanks to toritoribe-san.