Here, you get a chance of an increased rate with the more Pokémon of the species you have captured.
In previous games this included Catch Combos, SOS battles and DexNav, and with this Pokémon Sword & Shield takes it further by altering the DexNav method from Omega Ruby & Alpha Sapphire. Shiny Hunting is a concept where you can improve the odds of a Shiny Pokémon by doing certain tasks. However, due to a programming quirk, at time of writing when you encounter a shiny Pokémon as a standard wild encounter, this is essentially inverted with a 4095/4096 chance of the Pokémon having the Squares sparkle and a 0.9375/4096 chance of it having the stars one when encountering a Shiny Pokémon. With breeding Pokémon, static encounters and Max Raid Battles, when you encounter a Shiny Pokémon it will have a 15/16 chance of being a Pokémon with the Stars sparkle and a 1/16 chance of having the Squares sparkle. To get the different effects is quite simply explained as random chance.
There's the traditional stars and a new effect featuring spinning squares. In Pokémon Sword & Shield there are two kinds of shiny animation variety. You will also not see the Pokémon as shiny in the overworld until you encounter it. You also cannot get given Shiny Pokémon including starters (although they can be bred), Type: Null and the Gigantamax Pikachu & Eevee gifts. For Pokémon that are restricted, they are set to prevent it from being shiny. Pokémon Sword & Shield has a change where you can now encounter Pokémon at majorly higher levels than you and thus get restricted from capture until you have certain badges. This changes it to 1 in 682.7 without a Shiny Charm or 1 in 512. The rates can be improved further by breeding with Pokémon from a game in another language. First, the Shiny rate is the same as it has been at since Pokémon X & Y with it being 1 in 4096 as standard, or if you have the Shiny Charm you obtain for completing the Pokédex, the rates are 1 in 1365.33 Shiny Pokémon have been a staple in Pokémon since Pokémon Gold & Silver and returned once more in Pokémon Sword & Shield. Black: Victini & ReshiramWhite: Victini & Zekrom.Pokémon Ranger & The Temple of the Sea!.Mystery Dungeon - Explorers of Time & Darkness.Mystery Dungeon: Blazing, Stormy & Light Adventure Squad.Pokémon Battle TrozeiPokémon Link: Battle.