you complete the national pokedex
pokedex or National
You get the national pokedex and a jhoto starter.
Do the aftergame stuff
im pretty sure u get a national pokedex (national dex)
Complete the Unova pokedex (after that coplete the national pokedex)
You go outside...
oak will thank you on the PC that is it what a blow out
you unlock a special stage where you can battle mew two
If you complete the national pokedex, go to visit Prof. Oak and he will give you a ticket to a place called foggy valley. You have to get a ticket because it is also an island.
not much your pokegear turns a different color
You have to complete the Sinnoh pokedex before haveing the national pokedex.
If you complete the pokedex you can get a diploma from game freak in the celadon mansion in celadon city and you can now say to everyone you did it!