When did Yamamoto learn about the Maffia stuff?

Yamamoto-kun starting to learn about the Mafia stuff during real battles.When he was being graduated from Namimori Middle School,he starting to grow being più mature and finally learned everything(including Lambo's Ten anno Bazooka)in the future.In the future,he also starting to forget all about baseball and focus all to his sword after being tutored da Squalo.In Namimori Middle,it is also stated that some 1st-year students joined the baseball club because of him,because he has become the legendary baseball player in Namimori.Future Yamamoto has shown to have learned everything about the Mafia and seems to be okay with it.

He realize it was a real mafia stuff after his father was killed