DPPt Underground item RNG

Overview

This guide will teach you how to RNG manipulate mining spots inside the Underground in Pokémon Diamond, Pearl and Platinum versions to be able to get whatever items you want quickly.

Due to personal time constraints, this is only a "quick" guide instead of a "full" guide, meaning the explanations may not be quite as exhaustive and detailed as usual, though knowing me I won't be able hold myself back and still write a LOT. Primarily this being a "quick" guide means that there'll only be very few pictures, if any, as making those takes up like 50% of the time when I work on a guide.

Let me first explain how the Underground generates its "random things".

The Underground mainly uses 2 separate RNG algorithms to determine all the random things within it. Both of them are completely independent of the usual "Initial Seed" you're used to hitting for any other RNGs in Gen 4 like Wild or Static RNG.

The first of the two decides the locations of mining spots and traps, how much buried spheres grow and what inventory and prices the Vendors have.
This algorithm cannot currently be feasibly RNGd, as it uses a daily Seed similar to the Group Seed. It is decided whenever the player clicks on "New Game" upon creating a new savefile, rather than of together with your TID/SID. In theory one could manipulate this Seed or try and deduce it later on from the Vendor inventories or mining spot spawning locations, but since that didn't seem all that useful and quite cumbersome, I did not make a tool for that.

The second one however is more interesting, as it decides what items will spawn inside mining spots. This also means that it does not matter what mining spot you walk to first or how long it takes you to get there, as you will always get the exact same items.
This RNG Seed is determined anew every time you enter the Underground. The final A-button press here is on the second save confirmation right before you enter the Underground and uses the current Date, Time and Delay. Whatever "regular" Initial Seed you hit before entering the Underground does not matter at all.
Therefore it is very feasible to hit a specific Underground item RNG Seed.
I will refer to this RNG Algorithm as just the "Underground RNG" for the remainder of this guide.

Recommended setup

Hardware requirements

• Pokémon Diamond, Pearl or Platinum and any model DS Console or an NDS Emulator of your choice

• a Windows 10/11 PC, MacOS Sequoia/Tahoe/Golden Gate or Ubuntu 24.04/26.04

In-Game requirements

• You must have been to the Underground at least once and dug up at least 1 mining spot (doesn't matter whether you got any items or not), as the very first mining spot is partially scripted and generates differently from all future mining spots.

Tools used

You will need a special version of PokéFinder called "Nick's Fork of PokéFinder", as the Underground RNG tool is not yet available in the main PokéFinder program.

• Nick's Fork of PokéFinder version 5.3.4 or newer

Video example

• None yet

The Guide

General info about the tool

To begin, start PokéFinder, go to the Gen 4 Tools in the top bar and open the Underground tool.

Once opened, have a look at your profile at the top. There's a new field that you can edit either from within the Underground Tool or from the profile editor for the Type Plates. This is important, as you can dig up exactly 1 of each Type Plate in the Underground. Once you have recovered a Plate, it can never be dug up again. This slightly changes the generation of items whenever the game tries to spawn a Plate in a mining spot, so for accurate results, note down which Plates you have dug up in the Underground already in that selector field.
Unfortunately, there is no way to easily check which Type Plates you already dug up inside the game, but if you always explore every area and pick up all items and hidden items, you should already have 1 of each Plate. So checking what Plates you have 2 of could be useful here (also keep in mind that there's a third Flame Plate you can get if you bring Arceus to Oreburgh Mine in Platinum).

The Underground tool has 3 main tabs: the Generator, Finder and Searcher:

• The Generator works like most other Generators and helps you reach your target Advance.
• The Searcher also works like most other Searchers and lets you search for potential target Seeds that have the "things" you need.
• The Finder is brand new here however. It basically replaces the bottom half of Seed to Time, as it is used for Seed confirmation.

There are 3 ways to RNG the items in the Underground:

1. You search for and then try to hit a specific Underground Seed that has 1 mining spot with a set of up to 4 items that you want, and you don't stop until you hit your target Seed. This is mostly useful if you're looking to just quickly get up to 4 of one or a few specific and generally rarer items.

2. You search for and then try to hit a specific Underground Seed that has 2 or more consecutive mining spots with items you want, and you don't stop until you hit your target Seed. This is best used if you're looking to farm a lot of a specific item or item category (like evolution stones for the Pokédex or Fossils to unlock the Red Crystal Secret Base decoration, since it requires the player to have dug up 100 Fossils total).

3. You search for and then try to hit a specific Underground Seed, but you just RNG on whatever Underground Seed you happen to land on instead of trying to hit your target again and again. This is generally more useful if you're just looking for a small amount (1-3 or so) of only one or a handful of different items (excluding Type Plates due to their extreme rarity).

You can check for how rare each item is via the "Check Item Odds" popup by clicking the button on the top right.

Just keep this in mind for the next "Finding a target Seed" section, so you don't waste a lot of time trying to search for some hyperspecific item combo when you don't actually intend to "farm" for a lot of items. I will explain all three of these ways to RNG in more detail later on in this guide.

Finding a target Seed

Switch to the Searcher tab and you'll be presented with 5 separate sections.

Begin with the Filters section. Here you can input how many of which item(s) you want. You can search for up to 4 different items at a time. You can also set how many of an item you wish to get. By default, this is limited to 4 at most, and only if you only selected 1 specific item, as a mining spot can have between 2-4 items, never more or less than that.

Now let's have a look at the RNG Info section. Here you can put the date range, Delay range and how many consecutive mining spots to search through. Each additional consecutive mining spot will increase the amount of items you can search for in the Filters section by 4. This will also increase the search time exponentially, so I don't recommend searching for more than 3 mining spots in a row (on my old laptop, 4 was still doable but 5+ would just take literal hours; your mileage here may vary depending on how good your PC is. The max mining spots the searcher can search through is 8 consecutive ones). For now I recommend staying with the default Delay range and only searching through 1 month of your choice. A target Delay below 1400 is very difficult to sometimes impossible to hit; anything at or above 1400 is perfectly reasonable however.

One last thing to think about is whether you want to enable the "Consider a Plate recovered for subsequent spots, even if that Plate is not the target".
If you're searching for a specific Plate or for "Any Plate", the program assumes that you will pick up that / all Plates you come across. As explained earlier this can affect the item generation slightly. This option lets you decide whether you wish to pick up any Plates you come across, even if you are not searching for any Plates.

Once you've chosen how many of what items you want and how many consecutive mining spots to search through, you can press on Search.

If you can't get any results for your wishes, increasing the date range to search through is vastly more useful than increasing the Delay range.
But I must warn you that hyperspecific item combinations are very rare. You will have a difficult time finding 3-4 of any specific item on multiple walls in a row, since about 64% of all "items" that spawn in mining spots post National Dex (or 83% pre National Dex) are Spheres. Especially some of the rarer and/or larger items like Star Pieces or Fossils will be difficult to find many of. Common things like Heart Scales should be a bit easier to find in larger amounts, but 4 in each consecutive mining spot is still highly unlikely, so manage your expectations.

With at least one result found, it'll tell you your target Seed, target Delay, the items on the very first mining spot and how many items and consecutive mining spots the searcher found in total.
You can also click on a searcher result and the preview of the mining spots will populate in the top right. This is purely visual for you with little functionality here; you will see the preview in the Generator later on as well.

In the bottom right is your "Seed to Time" section where you can see what times you can use to hit this Seed. You may also notice a quirk of Underground Seeds here, which is that with each decreased target second, the target Delay increases by 1 and vice versa. More on this later during the "The RNG Process" section.

The RNG process

With a result found, you now just have to try and hit it. This works largely like hitting your regular initial RNG Seed for a Wild or Static RNG, just that instead of continuing your savefile from the main menu on the end of the second part of the timer, you now go to the Underground. To make this as smooth as possible, I recommend to put the Explorer Kit onto the Y shortcut, since time may already be short if you're going for a target Delay at or around 1400 and navigating through the bag takes a fair bit of extra time.

So open up EonTimer, put your target Delay and target second into their respective fields and set your DS clock to the appropriate time accounting for any "minutes before target" EonTimer may tell you about.

For the target second, I personally like to try out which one would give me the lowest possible, but still feasible, amount of wait time for the first part of the timer. If I e.g. go for a target Seed at 1400 Delay and use a Calibrated Delay of 600 in EonTimer for my usual RNGs, I would try to aim for a slightly different target Delay that has 40 as the target second, as that would only have me wait 12 seconds for the first part of the timer which is neither too much nor too little for my DS. If you're on DSi or especially 3DS, you will probably want to aim for a target second that gives you around 40 seconds for the first part of the timer.
If you also did this, don't forget to find a target time that has e.g. 40 (or whatever number you picked) as the target second and then adjust your target Delay in EonTimer according to that target time's Delay and your DS console's clock according to whatever time it ended up being.

Before you begin, you should boot up the game once already on your target date and save the game to get the Journal popup to go away, as it may otherwise impact the RNG a bit (exact extent of its impact requires more research, but it seems to at least flip the Delay you'll hit for the Underground Seed between odd and even for some reason).
No matter what, just make sure to be consistent with what you do between attempts, as it seems that activating the Explorer Kit via Y makes the game generate the Underground Seed about 120 Delay (or 2 seconds) slower than when it generates if you activate it from your Bag. This is neither good nor bad, but kind of pointless for us, as the additional time it takes to get into the Bag effectively lets you hit just as early of a Delay as using the Y shortcut does. Just do whatever method you find more comfortable.

Once you're ready, go back to the DS time settings and start EonTimer at the same time as you set your DS to the target time, just like you would for any other RNG. Then get back to the home menu and get ready to launch the game (or soft reset it) at the end of the first part of the timer.

Now you load into the game as swiftly as you can to not waste any time, activate the Explorer Kit and wait at the very last save confirmation textbox (for english language games, it's "There is already a saved file. Is it OK to overwrite it?"). Whenever you "continue your adventure" by loading your savefile does not matter at all; the regular initial Seed has no impact on the Underground Seed.

The moment the second part of the timer ends, you click on YES to save the game and get into the Underground.

Identifying what Seed you hit

Next up is identifying what Seed you hit. For this you must first find a glowing spot in the wall that you can mine in. Literally any spot will do, the items you get are the same anyways.

Once you've opened up a mining spot, it's best to read how many items the game told you it found, though it's not absolutely needed for this. It just helps a little bit. Make sure to not mine ANYTHING yet though. Best not to touch the touchscreen at all for now.

In PokéFinder, right click on whatever target date/time and Delay you chose in the Searcher tab's Seed to Time section and "Go to Finder".
This will immediately bring you over to the Finder tab and fill out all relevant target Seed information for you.

In the Finder, there are 6 separate sections.

Firstly there are the "Your Current Mining Spot" and "RNG Info" sections.
Input the mining spot dirt that you see on the bottom screen on your DS into the "Your Current Mining Spot" field, as this is what we will use to confirm the Underground Seed you hit. You do not need to be perfectly accurate. I generally like to just set the brush to 2x2 and fill in where there's larger sections of darker or rocky dirt. This is also what the "Max Tile Mismatches" field in the RNG Info section is for; it let's you tell the Finder tab to also consider results that don't match up perfectly with the 130 tiles of the mining field UI you adjusted. If you plan to perfectly match the game, which you certainly can, just set that field to 10 in case you made a few smaller errors. Otherwise just leave it at the default value of 30. If you remembered to check for how many items were found in the wall, you can also input that into the "Item Count" field. Leave all the other RNG Info section values at their default (such as +/- 500 Delay).

Next press the Search button and see if any of the results that appear in the bottom left table match the mining field you're presented with ingame. If you click on a result, that Seed's first mining field will appear in the "Selected Seeds Mining Field" UI for you to compare.

If you find that none of the results match, double check you didn't make any mistakes with the date or time in your DS, your EonTimer setup, the mining field you input and just try again even if you cannot find any mistakes. If this persists, join im a blisy ._.'s RNG manip assistance Discord server and ask for help in the dppt_hgss channel providing an explanation of the issue and full window screenshots of your PokéFinder Underground window Finder and Searcher tabs and EonTimer.

But if you do get a perfect match and it is not your target Seed, which is fairly likely, there are now 3 ways to continue that I alluded to earlier:

1. If you intend to just quickly get up to 4 of one or a few specific and generally rarer items, continue trying to hit your specific target Seed.

2. If you intend to farm a lot of one or a few items and searched for a Seed that satisfies your fairly specific wishes, also continue trying to hit your specific target Seed.

3. If you just intend to get a few not particularly rare items, you can just continue to RNG on whatever random Seed you just hit and manipulate what items you get from any later mining spots.

In the cases of options 1. and 2., input whatever Delay you hit into EonTimer's "Delay Hit" field and click the Update button to adjust your Calibrated Delay, then do the next RNG attempt. Should you notice that you keep hitting the wrong Delay parity (e.g. your target Delay is an even number, but you keep hitting uneven Delays), just increase or decrease your target second in EonTimer and the Finder tab's RNG Info section by 1. This will effectively swap the Delays between odd and even for you.

In the case of option 3, or once you've hit your target Seed for options 1. or 2., it's time for the next phase of the RNG.

Getting your desired items

If the items of whatever single mining spot you're now on right now are enough for you, you could simply dig them up now and be done with the RNG, in which case you can stop reading.

But if you want to get some more items, you have the option to now manipulate what items the next mining spot will spawn, which may be necessary if you searched for 2 or more consecutive mining spots and want to get all of those items. This is generally done by using the Pickaxe and Hammer tools in a specific order on your current mining spot, but more on that in a bit.

If you searched for and hit a 1 mining spot target Seed or if you just hit a random Seed that you wish to go with, continue reading here.

If you searched for 2 or more consecutive mining spots, skip ahead to the Advancing the RNG to reach your desired items section.

Searching for further items

With the Seed you're on identified, you now have the opportunity to search for further items on this Seed.

This is done in the Item Finder section of the Finder tab. If you click on the Seed you just hit in the bottom left results table, it will automatically copy that Seed into the Item Finder section's Seed field.
Now all that's left for you to do is to specify what item(s) you're looking for and how many consecutive mining spots you wish to search through. Don't forget that the more mining spots you search through, the longer it will take. I generally recommend to only search through 3-4 at a time, though my old laptop may not be the best baseline for this. You can always start another search from a later mining spot as well.

Once you're done inputting your desired settings, press Search and PokéFinder will find you the optimal route to get as many of your desired item as possible within the selected max mining spots.

Advancing the RNG to reach your desired items

In the Finder tab, right click the Seed you just hit in the bottom left table and "Open in Generator".

In the Generator you are presented with all the possible item constellations you could reach and a suggestion of how to reach it using a combination of Pickaxe and Hammer hits. You could theoretically use many different combinations to reach the exact same set of items, however since advancing the RNG that way can get quite complicated for the Underground I opted to not display the actual RNG Advances that the game is using in the background, but only display all the relevant ones with item sets you can actually reach and a way to reach them.

Generally I'd recommend to now enable the "Only display target Advances" checkbox in the settings section, as that will hide all the Advances that you likely wouldn't want to hit. You can also just scroll to your target Advance though if you wish.

In the Hit Sequence column, you can see how you must use the Pickaxe and Hammer tools to advance to your desired next item set. P stands for the Pickaxe and H for the Hammer.
Next there is the Recovered column, which specifies what items you must and must not recover.
And lastly comes the Outcome column, which can either say "All Items Recovered" or "Wall Collapsed".
For example a "4P, 5H, 10P - 1, 2, 3, 4 - All Items Recovered" set of instructions would mean you have to use the Pickaxe 4 times, then the Hammer 5 times and then the Pickaxe again another 10 times whilst making sure to recover all of the items.
Would you instead get instructions like "5H, 39P - 1, 2 - Wall Collapsed", you would have to use the Hammer 5 times and then the Pickaxe 39 times whilst only recovering the specific 2 items labeled as item 1 and item 2 right below the top left "Current Mining Spot" display.

One other VERY important thing to note is that you cannot just hammer away at your touchscreen to e.g. get the wall to collapse quickly. A mining spot has 196 "health". Each Pickaxe hit does 4 "damage", whilst each Hammer hit does 8. Once the mining spot goes below 170 health, a screen shake animation will start to play after every single hit. So e.g. on the 8th Pickaxe or 4th Hammer use (or a combination) these animations start and they actually advance the RNG forward as well. Since they do so every 1/30th of a second whilst the animation is playing, which would make it very difficult to perfectly time stopping the animation, I configured the Underground tool to always assume every single shake animation can play out in full. So you must wait the 1 full second that it takes for the shaking animation to end after each hit to be able to hit your target Advance and item set.

Preparing to continue with the next mining spot

Once you've excavated your first mining spot following the instructions that lead to the second mining spot, you can begin this process again and continue towards a third mining spot.

If you did not search for a result that includes that third mining spot, you can instead go back to the Finder tab's Item Finder section and do so now.

But if you already searched for a result that includes that third consecutive mining spot, you can now just right click your target Advance in the Generator and "Set as current Mining Spot" to be shown all the reachable Advances for that third mining spot (or just the target if you enabled the checkbox).

From here on out, it's just a constant rinse and repeat until you either got enough items or get tired of this RNG.

Next steps...

And that's all; now you know how to RNG manipulate items in the Underground.

Thank you for reading and have fun RNGing!