yet another question

[?????????]

You know the rock at the end of route 224? When you click on it, a box comes up that says "The surface is unmarked. It is polished like a mirror." What is it for?

[chikorita]

In Platinum, when I got Oak's Letter, I went there for Shaymin and was told to "Inscribe the name of the person who inspired me the most" or some such. Pretty sure that's the rock you're talking about.

[?????????]

Whern/how do you get the letter?

[chikorita]

You have to get it from mystery gift. If you haven't got that, pretty sure Serebii will tell you how. Better hurry, I don't think the event will last much longer.