Squirtle starters can capture lightning dog Raikou. Bulbasaur starters can capture fire dog Entei. Charmander starters can capture water dog Suicune. [1] X Research source

You must return to Professor Oak’s house at the beginning of the game to get your national Pokédex. [2] X Research source

You can also ride the bike to move around faster.

Max Repels work for roughly 250 paces before you need to use a new one. [4] X Research source

Your best bet is to set a Level 49 Pokémon first. This way you will only find Pokémon level 50 and up, which only includes the dogs.

If you accidentally KO the dog it will not appear again later in the game. Remember, however, that as soon as you try to go to the dog’s current location it will move. Check your Pokédex every time you enter a new area to see if it is in the same place as you.

Any damage you do to a dog will last. If you run into them once and bring them to half health before they run, they will still be at half health the next time you see them. [8] X Research source

Suicune has a speed rating of 85. Entei has a speed rating of 100. Raikou has a speed rating of 115. [9] X Research source

Attacks like Wrap and Fire Spin do damage over a few turns and will keep Pokémon from running. They will last for 3-5 turns before needing to be re-applied. [10] X Research source

Sleep Spore Paralyze Poison.

The attack “Taunt” will negate the effects of Roar, but you need to use it your first turn to be effective. [11] X Research source

Don’t ever gamble with a big attack – if they run before you capture them they will reappear with the exact same health they left with. This means you can take your time.

You will likely need 50 or more Ultra Balls to succeed. You would rather have them, after all, than run out of them when you need them. Timer Balls, which gain power the longer the battle goes on, reach their peak performance after 25 turns. Use your Ultra Balls to weaken the Pokémon, then launch your Timer Balls later in the battle to use them effectively.

Remember, however, that you only get one Master Ball in the game. That said, this is one of the perfect places to use it.