You will receive a Master Ball after defeating the Elite Four that you can use, but you might want to save that for more difficult Pokémon such as Volcarona or Kyurem. Reshiram can only be caught in Pokémon Black. If you are playing Pokémon White, you will need to trade for Reshiram.
You will be able to change your party after fighting the Elite Four, so don’t worry if you don’t have the right group for catching Reshiram.
To make catching Reshiram as easy as possible, make sure your party has a Pokémon that knows False Swipe and a Pokémon that knows a move that causes sleep or paralysis. You may need four to six Timer Balls. You can leave the castle if you need to get some more supplies or level your Pokémon up some more. Go to the third room from the right on the third floor of the castle. Talk to the Plasma Grunt and you can be teleported away. When you’re ready to return, talk to the Grunt at the Pokémon Center at the Pokémon League.
Reshiram is weak to Ground-, Rock-, and Dragon-type attacks. Once Reshiram is asleep or paralyzed and at 1 HP, start throwing Ultra Balls at it. If it wakes up or becomes able to move again, use the move again. Keep throwing balls! You may not catch it on the first ball, but you will catch it eventually. If you fail to capture Reshiram here, you have another chance in doing so at the 7th floor of Dragonspiral Tower, which can be found to the north of Icirrus City. [1] X Research source This is also where Reshiram can be found in White 2 once you receive the Light Stone from N.
