I know you can I just dont know how.you CAN fight no.2 no.1 no.1 and sinnoh ash
to battle Blue in Pokemon Heartgold you must defeat the 7th gym leader, then find him on cinnabar island. Talk to him, then he will go back to his gym for you to fight
You have to go in the lighthouse and get the gym leader. Then you fight the gym leader and the guy in front of the town will leave and you will be able to get there.
Go back to Olivine City and give the medicine to Jasmine. Then fight her at the gym.
You can fight the Kanto Gym Leaders in any order, except Brock, Blaine, and Green/Blue.
Yes, you can fight the Kanto Gyms in Pokémon HeartGold.
Sorry, you can't in Pokemon Heartgold. But you can in Emerald, Ruby, Saphire and crystal.
Complete sinnoh dex
Blue is on Cinnabar Island. But to be able to fight him, you must find Blaine the old Cinnabar gym leader. He is in the seafoam islands. Beat him, and then talk to Blue again. He will then return to his gym, where you can fight him!
no sorry...
Travel around sinnoh
135 on the Sinnoh dex is Lumineon, you can catch a Finneon with a good rod and evolve it, or you can fight a trainer on route 223 who carries one.
About 10 times then you can fight your rival at certain days at the Pokemon League.