Editor’s Note
This guide explains how to obtain the essential Drill tool in Pokémon Brilliant Diamond and Shining Pearl, which is required to build a secret base in the Grand Underground.
The first step to creating a secret base in the underground caves is to obtain the Drill (in addition to, obviously, unlocking access to them in Eterna City). This is a tool that will allow you to create the base anywhere you prefer in the tunnels.
You can easily get your first Drill by completing the first mission given to you by the Underground Man in Eterna City. You just need to go down to the caves and excavate for treasures for the first time in a vein. After this, return to the Underground Man and he will give you a Drill if you talk to him again in his house.
Remember that the drill is consumed when creating the base for the first time, so if you want to move the base location later, you can always get more drills by buying them from the vendors that appear in the tunnels in exchange for the gems you have accumulated during your excavations.
Once you have your Drill, creating a secret base is very, very easy. So easy that you probably won’t need our help, but just in case, here’s how to create it.
Descend to the Underground Caves when you already have the drill. In the tunnels, look for a location where you would like to create your base. When you have found the place where you want to create the base, approach a wall and press the A button. The game will tell you if that is the place where you want to establish your base. Accept and say yes. Immediately, the entrance to the base will be created and your drill will be consumed.
For obvious reasons, you cannot create the base right on the same spot where there is a treasure excavation point or inside a Pokémon Hideaway, but otherwise, any wall in the tunnels is a good place to create it. As a recommendation, we advise you to choose a central location or where there are nearby vendors, to save yourself long trips and make it more convenient to access whenever you want to visit.
The particularity and appeal of having a secret base in the caves is that we can place Pokémon statues in them. And what are these statues for? Well, each statue serves to increase the frequency with which different types of Pokémon appear in the Pokémon Hideaways of the underground (note, only in the underground, not in the routes and areas of Sinnoh).
That is, to put it simply: if, for example, you have a Pikachu statue, it will increase the appearance frequency of Electric-type Pokémon in the underground hideaways. If the Pokémon on the statue has two associated types, then it will increase the frequency of both types (although its first type will always receive double the effect of its second type).
Each Pokémon statue has two versions: a normal version and a special version with a star symbol (shiny).
The statues occupy space in the base: they can be size XS (1×1), S (1×2), M (2×2), L (3×3), and XL (4×4). It is possible to place up to 18 statues in total regardless of their size.
The larger the statues: the greater their effect.
Normal statues: have a multiplier of x1 in their effect.
Special star statues: have double (x2) the effect.
Legendary Pokémon statues: have triple (x3) the effect.
You can also buy pedestals for the statues from the vendors in the tunnels. Although these pedestals are merely decorative and come in up to 5 different sizes.
Keep in mind that the appearance frequency bonus from statues is added up based on all the statues you have placed in the base. This bonus is only obtained for one type at a time, so if, for example, you have a normal M-sized statue of an Ice-type Pokémon, and a special M-sized statue of a Fire-type Pokémon, the bonus that will prevail will be that of the Fire type, since its statue has more “value”, so to speak.
Remember that you can interact with the sphere at the entrance of your base at any time to check which bonus is currently active. Another interesting detail is that the more statues of the same type you have placed, the more bonus points you will add and the greater its effect.
On the other hand, it is worth mentioning that if you play in multiplayer (local or online) in the caves, you can activate the effect of the statues that other players have placed in their own bases to take advantage of them.