Duel Monster II: Dark Duel Stories - Salomon Muto(or grampa) prizes. How to check if you have him.

[CuboMagico]

Not that I am planning to ever get 100% in this game but to clean my consiouness a little I need to ask. What exactly makes him appear? is it just a question of deleting your save until he appears? Is there a password to make him appear instead of Tea? he gives you exclusive cards so I would like to know if there is a way to make him appear without deleting my save.

[sol_warrior]

Unfortunately, due to the rarity of its appearance I haven't been able to find any information on which data file, hex value, etc. stores the value for that flag within the save file. If we can manage to obtain a valid save file that has the event activated then I can attempt to compare it with a vanilla save file.

Sadly even after decades of investigation by Japanese players, the specific conditions to activate Grandpa Muto in DM2 is still unknown. However, it appears that once triggered he will appear after each victory.

Gramps' appearance in this game is triggered so rarely that it was commonly believed to be an urban myth in Japan, but over the years it has been fully confirmed by multiple individuals and documented in photos and videos. At some point it was even believed that only a certain cartridge/ROM version contained that data, but that has also been debunked.

In the process of throroughly testing hundreds of cartridges and ROM revisions and experimenting with save files on each ROM revision, Japanese players GeeBee and SkyBlue have virtually confirmed that the trigger is not dependent on the ROM version, and instead is based on "something" within the save file. The specific trigger conditions still have not been discovered or verified.

GeeBee's research: https://x.com/search?q=GB%E9%81%8A%E6%88%AF%E7%8E%8B2%E3%81%AE%E3%83%8A%E3%82%BE%20from%3Aoppoko777&src=typed_query

Skyblue's research: https://x.com/search?q=GB%20%E9%81%8A%E6%88%AF%E7%8E%8B2%20%E5%8F%8C%E5%85%AD%E6%A4%9C%E8%A8%BC%E3%82%B7%E3%83%AA%E3%83%BC%E3%82%BA%20from%3Achoose_anything&src=typed_query

The trigger does not appear to be related to the Duelist Level, the Deck Volume, or the cards present in the Trunk. I tested these possibilities in the Early Days Collection by activating the "Unlock Cards" Enhancement feature though, so this does not disprove the possibility of it being activated by Téa's cutscene after being given specific card or cards in-game.

Over the years, some fans have speculated that the trigger may be related to the player's name, but my research and testing seems to disprove that. I was able to locate a video of a playthrough with Gramps appearing, and that player's save was named ぼるた (Boruta). He claims that Grandpa Muto suddenly appeared after defeating Yugi, but he was unsure what could have triggered it. I created a new save named "Boruta" with a fresh Switch profile, but it did not trigger the event. I also did the same with a Japanese save named 「ぼるた」 but it also did not trigger the event on either GB or GBC.

Video Link: https://youtu.be/ZU8gKa7Qmt0?list=PLf0pN-qOC0usMs-NquDmguIklyGnHssH-&t=326

My current working hypothesis is that the event trigger is related to the cards that are actively in the player's deck. In this game, the contents of the player's starting deck is randomized (or at least partially randomized) from a pool of beginner cards. I believe that there must be some combination of specific cards or types that trigger the required conditions when present in the deck.

That being said, it's not impossible for the trigger to be something else like completing a hidden challenge such as defeating a specific opponent by dealing the final blow with a specific card, or create X fusion cards in a single duel, or winning a duel with a deck exclusively consisting of cards under 500 ATK/500 DEF.

[mantidactyle]

Originally posted by sol_warrior:

Unfortunately, due to the rarity of its appearance I haven't been able to find any information on which data file, hex value, etc. stores the value for that flag within the save file. If we can manage to obtain a valid save file that has the event activated then I can attempt to compare it with a vanilla save file.

Sadly even after decades of investigation by Japanese players, the specific conditions to activate Grandpa Muto in DM2 is still unknown. However, it appears that once triggered he will appear after each victory.

Gramps' appearance in this game is triggered so rarely that it was commonly believed to be an urban myth in Japan, but over the years it has been fully confirmed by multiple individuals and documented in photos and videos. At some point it was even believed that only a certain cartridge/ROM version contained that data, but that has also been debunked.

In the process of throroughly testing hundreds of cartridges and ROM revisions and experimenting with save files on each ROM revision, Japanese players GeeBee and SkyBlue have virtually confirmed that the trigger is not dependent on the ROM version, and instead is based on "something" within the save file. The specific trigger conditions still have not been discovered or verified.

GeeBee's research: https://x.com/search?q=GB%E9%81%8A%E6%88%AF%E7%8E%8B2%E3%81%AE%E3%83%8A%E3%82%BE%20from%3Aoppoko777&src=typed_query

Skyblue's research: https://x.com/search?q=GB%20%E9%81%8A%E6%88%AF%E7%8E%8B2%20%E5%8F%8C%E5%85%AD%E6%A4%9C%E8%A8%BC%E3%82%B7%E3%83%AA%E3%83%BC%E3%82%BA%20from%3Achoose_anything&src=typed_query

The trigger does not appear to be related to the Duelist Level, the Deck Volume, or the cards present in the Trunk. I tested these possibilities in the Early Days Collection by activating the "Unlock Cards" Enhancement feature though, so this does not disprove the possibility of it being activated by Téa's cutscene after being given specific card or cards in-game.

Over the years, some fans have speculated that the trigger may be related to the player's name, but my research and testing seems to disprove that. I was able to locate a video of a playthrough with Gramps appearing, and that player's save was named ぼるた (Boruta). He claims that Grandpa Muto suddenly appeared after defeating Yugi, but he was unsure what could have triggered it. I created a new save named "Boruta" with a fresh Switch profile, but it did not trigger the event. I also did the same with a Japanese save named 「ぼるた」 but it also did not trigger the event on either GB or GBC.

Video Link: https://youtu.be/ZU8gKa7Qmt0?list=PLf0pN-qOC0usMs-NquDmguIklyGnHssH-&t=326

My current working hypothesis is that the event trigger is related to the cards that are actively in the player's deck. In this game, the contents of the player's starting deck is randomized (or at least partially randomized) from a pool of beginner cards. I believe that there must be some combination of specific cards or types that trigger the required conditions when present in the deck.

That being said, it's not impossible for the trigger to be something else like completing a hidden challenge such as defeating a specific opponent by dealing the final blow with a specific card, or create X fusion cards in a single duel, or winning a duel with a deck exclusively consisting of cards under 500 ATK/500 DEF.

Why do they need to make speculations ? Why did two persons (I can't read their post, I don't have an account on Twitter) need to do personal research ?

I already reverse-engineered the info back in 2023: https://datacrystal.tcrf.net/wiki/Yu-Gi-Oh!_Duel_Monsters_II:_Dark_Duel_Stories/ROM_map#Determines_if_Grandpa_is_activated

I already documented the result on yugipedia's DM2 article. There is nothing to research, nothing to discover, the info is already out there.

The HRAM address hFFDB is set when you create a new save file. 1 in 8 save files will have a 1/256 chance to trigger Grandpa at the end of each battle. The other saves will NEVER activate Grandpa.

[sol_warrior]

This is exactly the info I've been searching for, thank you. No idea why that page never appeared in any of my searches.

[Porky Minch]

Originally posted by sol_warrior:

Unfortunately, due to the rarity of its appearance I haven't been able to find any information on which data file, hex value, etc. stores the value for that flag within the save file. If we can manage to obtain a valid save file that has the event activated then I can attempt to compare it with a vanilla save file.

Sadly even after decades of investigation by Japanese players, the specific conditions to activate Grandpa Muto in DM2 is still unknown. However, it appears that once triggered he will appear after each victory.

I'm no code expert but I decided to do some research. Data Crystal (which I guess is an offshoot of The Cutting Room Floor?) has a few pages with all the ROM and RAM values for Duel Monsters II and it claims that only 1/8 save files are able to have Grandpa appear based on a Pseudo RNG call when the file is created. If you have a lucky save file then there's a 1/256 chance to have Grandpa give you a card after each duel. I'm not very knowledgeable so I can't tell whether it permanently enables him or if you only get a card for winning that one duel, but to me it seems like the latter. As far as I can tell the only time outside of making a new file that the PRNG function gets called is when you start a duel.

I'm unsure how it gets a fresh PRNG value when starting a new file though. I'm wondering if the person in that YouTube video used debug mode or a cheat code? Or maybe something is corrupt which causes Grandpa's PRNG check to always succeed?

Idk but here's the page I've been reading so someone else can hopefully figure this out.

https://datacrystal.tcrf.net/wiki/Yu-Gi-Oh!_Duel_Monsters_II:_Dark_Duel_Stories/ROM_map#Determines_if_Grandpa_is_activated

[Porky Minch]

Originally posted by mantidactyle:

I already reverse-engineered the info back in 2023: https://datacrystal.tcrf.net/wiki/Yu-Gi-Oh!_Duel_Monsters_II:_Dark_Duel_Stories/ROM_map#Determines_if_Grandpa_is_activated

Oops, I opened this thread hours ago and made my post without refreshing so I didn't realise that was posted already, lol.

Could you please explanation why the video sol_warrior posted is getting Grandpa after every battle? Because to me it doesn't look like he used the debug file and the data you reverse-engineered implies that Granpda isn't a permanent unlock.

[mantidactyle]

Originally posted by Porky Minch:

Originally posted by mantidactyle:

I already reverse-engineered the info back in 2023: https://datacrystal.tcrf.net/wiki/Yu-Gi-Oh!_Duel_Monsters_II:_Dark_Duel_Stories/ROM_map#Determines_if_Grandpa_is_activated

Oops, I opened this thread hours ago and made my post without refreshing so I didn't realise that was posted already, lol.

Could you please explanation why the video sol_warrior posted is getting Grandpa after every battle? Because to me it doesn't look like he used the debug file and the data you reverse-engineered implies that Granpda isn't a permanent unlock.

Once you get the good random number to trigger Sugoroku, it's permanent. It sets the bit 7 of hFFDB, once it is set you'll get Sugoroku after every battle.

Originally posted by Porky Minch:

I'm unsure how it gets a fresh PRNG value when starting a new file though.

It's in this subroutine: https://datacrystal.tcrf.net/wiki/Yu-Gi-Oh!_Duel_Monsters_II:_Dark_Duel_Stories/ROM_map#Blanks_SRAM_(B800),_set_(FFDB)_(FFDC)

[Porky Minch]

Oh nice! Glad it's permanent! Now if only there was a way to guarantee that a save file can get him that would be great...