You need to get the national dex, so you have to see all the sinnoh pokémon, then go to professer Rowan and he will give you the national dex as reward.
u have to get complete the national poke-dex by raymond
you fight it and defeat it w/ ur Pokemon
fight wild Pokemon and like 1/20,000 chances ur Pokemon that u have with u will get it
fight water Pokemon ( by fishing or surfing)
its between lake valor and sunnyshore city
Catch all the pokemon in the region. Get the national pokedex
u have to get complete the national poke-dex by raymond
ask who created pokemon platinum
You need to go to the fight area [at the top right of your map] and then you need to fill up your sinnoh pokedex first.then once you do that the people standing ,the ones blocking the water on the right side of town should not be there anymore! tada! chase peplin
Spear pillar
in the fight area
you fight your rival
You cant because they are different generations
obtain national pokedex
You can receive a Super Rod from a fisherman in the Fight Area on Pokemon Platinum, Diamond and Pearl.
To get past the people that are blocking your way, you need to see every Pokemon in the shinnoh dex and then get the national dex.
fight and ride!