As you know, at the beginning Pokemon GO invites you to choose between one of three initial Pokémon: Charmander, Squirtle, and Bulbasaur. This is in keeping with the original Game Boy games, which also had a choice between the starter trio.
But in fact, there is also a fourth option: Pikachu. The Yellow Pokémon is required for players to travel with it through the Kanto region. So here's what you need to do to get the famous Pokemon in Pokemon GO.
When Professor Willow tells you to make an initial choice, a starting trio will appear on the map. Typically, choosing one of the Pokémon will initiate a fight, which will result in you receiving your first Pokémon. If you haven't made a choice and just keep moving on, three will disappear and be reborn in front of you.
The yellow Pokémon is more difficult to obtain, as the game's camera keeps the trio on screen most of the time, and its GPS is still not the most accurate. But if you manage to ignore Charmander, Squirtle and Bulbasaur four times, their next return will happen together with Pikachu.
After Pikachu appears on the screen, you can select him and start the fight. The fight won't be the easiest, but this guy is worth getting.
