What is the best way to get rock hard knuckles...

Once you become a true warrior, you break bones every month and keep training and fighting despite it.

WAY OF THE ETERNAL WARRIOR

Do like the Koreans and wrap a rope around a tree and punch it

...

Do bear crawls on your knuckles. This is an old karate technique that literally makes your hands into weapons

i'm 12 and this is my first time on the internet? run away from this place kid and never look back

You are hopeless.

Practice on a proper punching bag before hitting walls like an idiot, preferably a nice leather bag filled with sand.
Keep in mind you have to start to learn not to fuck up your wrists and shoulders before you start worrying about harder knuckels.

>take bucket
>fill bucket with rice
>uncooked of course you mong
>plunge open hand in rice bucket
>start clenching hand and releasing
>sort of like kneading dough
>except it's going to hurt

Sauce: boxer having to do that shit every week

Use a punching bag.

Why don't you just do work with a heavy bag? all these retards saying punch your walls and thinking that turns girls on are autistic lmao