Having taken a break from Black & White, the Poké Radar makes it's triumphant return in Pokémon X & Y. After you have defeated the Elite Four, if you go to 2F in Sycamore's laboratoryand speak to the scientist, he will give you the PokéRadar. Each day, he will give you a Pokémon to study and, if you return having done a chain of them, you will receive an item such as an Ultra Ball.

The Poké Radar works similarly to in Pokémon Diamond & Pearl, but there are some notable differences. When you activate it in grass or flowers, up to five patches of grass will shake for a few seconds. The goal is to encounter Pokémon in the grass patches, defeat or capture them, and continue the chain. The higher the chain, the higher the IVs and shiny rate.

Around the player, there are basically 4 levels of square rings for each tile away from the player. Ring 1 is the closest while Ring 4 is the farthest. The Poké Radar will only activate in these rings if there is a grass or flower tile. Four of these patches will be within each of the rings, and can appear as rapidly-shaking grass patches or regular grass patches. If a tile has grass on it, then the chance of a tile activating are:

If you run around to charge the Poké Radar and then use the item to reset the grass patches, it will use the rate based on how the last encounter finished.

After all four rings have been checked for grass patches, the game randomly picks a location for a weaker grass patch in the rings 1, 2, or 3 squares away. If no grass patches are generated, the chain breaks.

The different types of grass have different properties:
Rapidly-Shaking Grass: Louder sound, side-to-side and up-down motion. Usually contains the chained Pokémon species and has the highest chance to continue your chain.
Regular Grass: Side-to-side motion. Usually contains a random Pokémon from the area and will break your chain if you encounter one that is not the chained species.
Weakly-Shaking Grass: Very little movement. Does not contain any Pokémon and instantly ends your chain.
Shiny Grass: Sparkle and a sound effect, and guarantees a shiny Pokémon.

There is one mechanic that can cause the rapidly-shaking grass and regular grass to appear differently. A rapidly-shaking grass patch has a 20% chance to appear like a regular grass patch, while the regular patches have a 10% chance to appear like a rapidly-shaking grass patch. Since the chance of a rapidly-shaking grass patch increases with ring distance, the ones further away from you are more likely to be true rapidly-shaking grass patches that continue your chain.

A number of things can break the chain besides walking into the weakly-shaking grass. These include running from battle, finding a Pokémon different from your chained Pokémon in a regular grass patch, talking to an NPC, using the Roller Skates or Bicycle, entering a horde battle, using a field move, battling a trainer, leaving the area, walking too far away from the active grass patches, fishing, picking up an item, and closing the game.

There are a few notable changes to the Poké Radar compared to Diamond & Pearl, however. First off, there is not a separate encounter table for the Pokémon in the area. As such, you will only encounter the Pokémon that are normally in the area. Secondly, as discussed previously, there are weakly-shaking decoy patches. These patches will shake, but when you step in them, it will tell you that there is no Pokémon there and your chain will be broken.

As the chain increases, the Pokémon encountered will have higher IV counts:

With each chain continuation, there is a chance for the music to change to a more upbeat tune. The upbeat music cannot start when the Poké Radar is used. While this music is playing, all rapidly-shaking grass has the maximum 1 in 100 chance to be shiny. The base chance for the upbeat music to start is 2%, but on the player's birthday (according to the 3DS profile), this chance increases to 4%. Each time an encounter finishes or the Poké Radar is used, if the upbeat music is playing, it has a 50% chance to end. If you catch a shiny Pokémon without the upbeat music active, the shiny rate will reset to 1 in 8100, but the chain will not. If the upbeat music is active, then the shiny rate will continue to be boosted according to the chain, even if the upbeat music ends. If you KO the shiny Pokémon, the shiny rate does not reset.