Cheat for it or go to an event.
In the battle tower cheat:aaadfde112345555343
you use a action replay and use it to get oaks letter
get the oaks letter cheat on the action replay and talk to the guy in the pokemart
u can put a cheat on ur action replay for oaks letter
You get oaks letter from a special event that is on the internet or wifi. you get it from any poke-mart in sinnoh
u need oaks letter that's where shaymin is get oaks letter.
that was an event to get shaymin! i dont think you can get it the only way to get oaks letter is from an AR code
Nintendo event or AR
you get it with a Nintendo event
no
Event or cheat
impossible
go to a Nintendo event.