BDSP Grand Underground RNG (CFW)


This section of the guide covers how to RNG manipulate Pokemon in the Grand Underground. Grand Underground Pokemon are generated upon entering the an underground cave and the Pokemon will remain the same until leaving the cave.

At this stage you should have already followed all of the setup and installation instructions found on the initial page of this guide.

Missed some setup instructions? Click here to go back!
How Does This Work?

BDSP has a constantly advancing seed which controls all random in-game events, such as which Pokemon you will encounter, if the Pokemon will be shiny, what stats it has etc.

We can use Moarencounterbots to monitor seeds in real time, as well as display how many advancements have occured from the starting seed, it can automatically advance the seed until a given point, then pause the game after a certain number of advancements have occured.

Essentially, Moarencounterbots is capable of doing the "chore" work automatically so you don't have to. You just need to search for targets yourself, let Moarencounterbots advance the RNG state, and actually hit the correct seed that produces the result you want.


With all the require reading out of the way, it's time to get to work!

The Process


First, you will need stand in the correct position in-game, then configure PokeFinder to match the details of the Pokemon you are hunting and set the desired search filters.

Figure 1 - Game Setup



Game Setup

Ensure you have all the required items and Pokemon you will need to successfully capture a Pokemon, after doing so, set your game up in this specific state:

  • Use the Explorer Kit to bring up the Grand Underground connectivity options, select the Play alone option.
  • Stand as close as possible to the cave that contains your desired Pokemon, then save the game.
  • Close and re-open the game. This will help to remove any unwanted advancements.
Restarting the game stops advancements from occuring when the game is paused on the Home menu, if you do not save and restart the game while underground your experience with this type of RNG will be a lot more difficult than it needs to be.

Figure 2 - PokeFinder Setup



PokeFinder Setup

Click the Gen 8 -> Underground button after launching PokeFinder to open the main window for underground encounters. Here is where we will fill in all the details about the Pokemon being hunted.

RNG Setup:
  • Select the correct profile from the dropdown menu at the top of the PokeFinder window.
  • Select the Lead if you are using a Pokemon with an influencing ability (like Synchronize).
  • In the Max Advances field, enter the amount of frames you are willing to search through.
  • In the Settings section in the middle, specify game completion status and encounter details.
  • Configure your search filters on the right, such as searching for a shiny, filters can be also combined for specific targeting.
Having a Pokemon with the ability Syncronize ensures that all encountered Pokemon have the same nature as your Pokemon. Your synchronizer needs to be first in your party in order to work.

Next, you will need to find your current seed, this can be done using Moarencounterbots (SysBot.NET).

Figure 3 - Finding Current Seed



Finding Current Seed

To easily obtain your current seed at any given point you can use the EncBotCopySeedBS bot routine in Moarencounterbots. You will need to toggle a few settings in the Hub tab for use with PokeFinder.

CopySeed Setup:
  • In the Hub tab, open the EncounterRNGBS dropdown menu.
  • Select Bit64PokeFinder in the DisplaySeedMode dropdown menu.
  • Set the MonitorRefreshRate to 0, this will be needed later.
  • In the Bots tab, type the local IP address of the console.
  • In the dropdown menu on the right, select EncBotCopySeedBS and add the bot.

When starting the EncBotCopySeedBS bot at any point your seed will be produced inside the Logs tab. These seeds can be pasted into the Seed 0 & Seed 1 fields of PokeFinder to search for targets that match your search parameters.


Save the game, then run EncBotCopySeedBS and paste the seeds into PokeFinder and hit search, repeat this process until a result that matches your search parameters has been found.

Figure 4 - Target Frame Found!



Target Frame Found!

In Figure 3, we can see that a Shiny Munchlax that matches the search filters has been produced in 165110 advances. This is the frame that we will aim to enter the Underground cave that contains the desired encounter.

Undesirable Result?
  • Reset the game to refresh the seed, then enter the underground overworld.
  • Run EncBotCopySeedBS again to produce a new seed.
  • Paste the new seeds into PokeFinder and search again.
  • Repeat until a desirable result has been found.

Consider increasing the search range if you are consistently finding "bad" seeds. Moarencounterbots is capable of advancing millions of frames with ease using the EncBotDexFlipBS routine. Alternatively you can opt to use less strict search filters.


From here you will need to advance towards your target frame. The majority of the work can be done using Moarencounterbots, but again this will require changing settings inside the Hub tab.

Figure 5 - Advancement Setup



Advancement Setup

To advance large distances as quickly as possible, use the EncBotDexFlipBS routine. A description of this routine can be found here. Having a decent chunk of your Pokedex completed is important for optimizing this method.

Settings Toggles:
  • In the Hub tab, open the EncounterRNGBS dropdown menu.
  • Set the MaxTotalAdvances value to ~10,000 frames before your target (e.g if Target is at 100,000, set to 90,000).
  • In the Bots tab, type the local IP address into the assigned field and remove any other active bots.
  • In the dropdown menu on the right, add both EncBotDexFlipBS and EncBotRNGMonitorBS

After the settings have been properly toggled, open the Pokedex in game, disconnect all controllers using the unsync button, then start the bot. The bot will automatically pause the game when the MaxTotalAdvances has been reached. You can then reconnect the controller once the routine has ended.

Controller Connectivity Troubleshooting
  • JoyCons - Slide the JoyCons onto the Joycon rail then press any button to sync them to the console.
  • Pro Controller - Reconnect the controller from the controller settings if you are having issues with automatically connecting, or the controller is synced as a second controller.
You do not need to use the Dex Flip routine if your target is of a small distance away, scrolling the Pokedex manually while monitoring your seed is effective enough in these cases.

Figure 6 - Dex Flip Complete



Final Advancements


Once you are close to your target frame (within ~10,000 frames), you will need to advance the rest of the way and hit your target frame slowly using EncBotRNGMonitorBS to monitor your seed.

The recommended method of hitting a target frame accurately is by pressing the home button twice to resume and pause the game to advance the RNG state as slowly as possible, this technique is known as "home mashing". While you can hit targets without using this technique, it is considered less consistent.

Final Advancements
  • With the game in the Home Menu, remove all active bots and add EncBotCopySeedBS to the bot list, then click the Start All button and paste your new seeds into PokeFinder, this will provide your new starting frame.
  • Remove EncBotCopySeedBS and add EncBotRNGMonitorBS instead, then start the bot to begin monitoring your seed. If done correctly the logs should start from advance 0.
  • Unpause the game and let the RNG state advance until you are within a few hundred frames of the target, then pause the game using the Home button.
You may optionally choose to manually advance the RNG state by scrolling the Pokedex. Be careful not to overshoot your target!
  • Remove all active bots, then run EncBotCopySeedBS and paste your seeds into PokeFinder, then search for your target frame again. Now re-add EncBotRNGMonitorBS once more.
  • Run EncBotRNGMonitorBS and use the home mashing technique mentioned above to inch towards your target frame slowly, once you hit the correct target frame keep the game paused on the Home Menu.
  • Unpause the game and quickly enter the cave by holding your joystick in the direction of the cave enterance, then find the expected species and initiate the encounter. If done correctly the encounter should match what is expected by PokeFinder.

Figure 7 - Target Frame Hit



PokeFinder displays the target on advance 118, and SysBot logs indicate that 118 advancements have occured, can now quickly enter the room and locate the Pokemon that we believe should be shiny (in this case, Munchlax). Then initiate the encounter and see if we hit the correct target frame.

Figure 8 - Result Found (PokeViewer.NET Confirmation)



After opening PokeViewer.NET and using the Battle View function, we can see that the Pokemon matches the PokeFinder search result. Mission accomplished!

Missing target frames? Click here for an encounter troubleshooting guide!