Why You Can't Get Them All:
* Version Exclusives: Some Legendary Pokémon are exclusive to either Black or White version. You'll need to trade with a friend to complete your collection.
* Limited Encounters: Some Legendary Pokemon are only found in specific locations, and they can be difficult to find.
* Events: Many Legendary Pokémon were only available through special events, which are no longer active.
How to Get the Most You Can:
1. Trade With Friends: This is essential for getting all the version-exclusive Legendaries.
2. Explore Everywhere: Pay close attention to the game's lore and clues to find Legendary Pokémon.
3. The Dream World: This online feature lets you interact with other players and potentially obtain rare Pokémon.
4. Breeding: Use the Breeding system to obtain Shiny Pokémon and other rare forms.
5. Game Corner: This location in Castelia City offers rare Pokemon, but you'll need to collect a lot of tokens to find them.
Here's a general guide on where to find some Legendaries and Rare Pokemon in Black and White:
* Landorus, Thundurus, Tornadus: Found in specific locations after completing the main story.
* Cobalion, Terrakion, Virizion: Found in specific locations after completing the main story.
* Reshiram/Zekrom: Version-exclusive Legendaries you'll encounter in the story.
* Victini: Can be found in a specific location with a unique method after completing the main story.
* Keldeo: Available through a specific post-game event.
* Genesect: Available through a specific post-game event.
Important Note: You will need to connect your Black or White game to the internet and use the Nintendo Wi-Fi Connection to access some post-game events and features.
For the most up-to-date information, I recommend checking online resources dedicated to Pokemon Black and White guides.