Do not let a Pokemon hold it for it to work.go to floaroma meadow.
going to the question "how do you get oak's letter in Pokemon diamond" to see the jokker and say to it if I kill it
You have to get oak's letter at on a special event.
Via Nintendo Wifi.
There is a road behind the Pokemon league where Shaymin can be found if you get Oak's letter.
no you have to get is from an action replay or go to a Pokemon event
Nothing unless you have Oak's Letter.
you need oak's letter from Nintendo event [which already past]
You use it at the smooth rock. Then you can get shaymin.It is on route 224.
route 224
You have to get it from an event, but there hasn't been any event lately for Pokemon diamond/pearl. Most of the events are for platinum now, oaks letter was given out a feew weeks ago for platinum. You can keep a look out though by going to serebii.net
Unknown(sorry about my spelling) Letter A is the rarest Unknown in all games. You are more likely to find a shiny Pokemon then Unknown A but if you are dedicated then go for it but prepare for frustration.
nope can't get that anser OPS! I have to go to school!