Serious Trainers in the Pokémon series obsess over the IVs (Individual Values) of the creatures they catch, and this will be no different for the competitive players of Pokémon Brilliant Diamond and Shining Pearl.
Combined with the Pokémon's EVs (Effort Values), these determine the maximum potential of the Pokémon.
What are IVs?
Pokémon have six IV values, covering HP, Speed, Attack, Defense, Special Attack, and Special Defense.
Each of these is assigned a number between 0 and 31. The higher the number, the higher the corresponding stat can potentially be.
IVs are set when the Pokémon is 'generated' -- when it pops up in the wild or is traded to a player by an NPC -- and cannot be changed thereafter. However, IVs can be gamed, for example through breeding Pokémon.
How to unlock the IV Judge function
In order to unlock the Judge function, you first need to beat the Elite Four.
Then, head to Snowpoint City and take the ferry to the Battle Tower.
Inside, there's a man on the far right, behind the guy with a Pikachu. He'll add the Judge function to your PC.
Since Generation VII, it has been possible to use Bottle Caps to maximise an IV of a Pokémon, providing it's Level 100. Be mindful that this Pokémon won't pass on those IVs when breeding other Pokémon for perfect IVs.
Use the table below to compare the Judge function's reaction with the relevant IVs.
Stay tuned for a dedicated guide to producing perfect IV Pokémon!