Here's how it works:
* Shiny Chance: Without the Oval Charm, the chance of encountering a Shiny Pokémon is 1/4096, or about 0.024%.
* With the Oval Charm: The chance increases to 1/1365.33, or about 0.073%. This is a significant boost, almost tripling your chances of finding a Shiny!
How to Obtain the Oval Charm:
* Complete the Pokédex: You need to have seen and registered at least 150 Pokémon in your Pokédex (which can be done in the Unova region).
* Talk to the Professor: After completing your Pokédex, go back to Professor Juniper's lab in Nuvema Town and talk to her. She will give you the Oval Charm as a reward for your accomplishment.
Note: While the Oval Charm increases your chances of encountering Shiny Pokémon, it doesn't guarantee you will find one. It still comes down to a lot of luck and persistence!