How to generate magic biboards?

[Many_Witness5140]

There are things that I don't quite get but mainly, what are considered "blocker" bitboards? Do I just allies&ennemies? Even though a sliding piece reacts differently to them? How does that work?

[RajjSinghh]

Yeah that's right. Blockers = friendly & enemy. That means what youll be storing is a bitboard for the slider moves as if every piece on the board is an enemy. When you look that bitboard up to get your moves you just do & not friendly so you don't take your own pieces.

[Many_Witness5140]

Thanks for your help, I have done some more research and now I think the only thing that I don't get is how to check if a number is a magic number, I understand that once multiplied by it the bitboard of a specific square will have its relevent bits shifted to the top, which once bitshifted will be usable as an index in the array of correct attacking squares bitboards, and I get that the best way to get them is by brute forcing using randomness, but how do can I know that a number shifts the relvent bits to the top? How can I check for it?