how and where can we catch the (bright)#201 in pokemon gold?

Question

after i get all those 26 unknowns

Answer 1

the bright, alternate color has nothing to do with getting the full list of 26 unknowns. any such stories you've heard are lies and rumor

the only thing that getting all 26 will do is if you have a gameboy printer, you can print things with an unknown border or something like that

EVERY single pokemon has like a 1 in 8,256 or some such chance to be shiny, *every* time you encounter one

because of the fact that EVERY unknown you come across in the alph ruins has the same exact % that it will be shiny, there is no specific time or place where you will encounter it.

it is random, and is exactly the same as catching a shiny larvitar.