Oak's letter is in diamond, pearl and platinum and it doesn't give you jirachi it gives you shaymin.
yoy have to get oaks letter, then go to route 224 and go to the big rock and proffessor oak should be there yoy have to get oaks letter, then go to route 224 and go to the big rock and proffessor oak should be there yoy have to get oaks letter, then go to route 224 and go to the big rock and proffessor oak should be there yoy have to get oaks letter, then go to route 224 and go to the big rock and proffessor oak should be there
go to a Nintendo event.
go to where Oaks letter is and go to where Shaymin is then that is where is should be
from a event or a cheat but you have to go to a pokemart to get it in the game
i think you have to go to the top of route 224 and go to the big rock thing and use oaks letter but im not sure because i cant get oaks letter :(
you need oaks letter and you need to go to a Nintendo event to get the letter
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
you need to go to a Nintendo event or get a action reaplay
get the oaks letter cheat on the action replay and talk to the guy in the pokemart
you go to route 224 in Pokemon diamond and oak will be there and u can catch shaymin!
you have to go to full moon island and play the azure flute the kiss your frenid then get the five star in your case go and catch jiratchi then taik to oak then you should resve oaks letter