RNG Manipulation
8 years ago
California, USA

So I've been doing some digging into the RNG in this game and I think I have a decent idea of how it works. First of all, it's a 4 byte unsigned(?) at address 0x009010. Now, there are many things that advance the RNG but I'll focus on the most important 2 first (NPC and Encounters. 3rd is battle actions). As of right now, the only 2 ways I know to reset the RNG is to hard reset the game and to fly to Magician's Island. The reset will always start you on the same value but I'm not sure how the Magician's Island one works.

  1. NPCs So this one is the biggest hurdle in manipulating the RNG. This advances the RNG every frame when you are in an area with a moving NPC. Now trying to hit an exact frame isn't exactly reasonable, but you can hit the frame you're looking for by using movement as a counter. Also, it would not be completely unreasonable to RNG manip straight from a new game. The biggest hurdle would be Kraze. Since we need to talk to him and the RNG advances every frame in this room, you would have to talk to him at the correct frame or at least close to it. So this part would require the most precision. Everything else is either automatic or easily doable if you leave Gregminster to go for Holy Rune before going to Magician's Island.

  2. Movement on screens with random encounters So this one is the really important one that will let us manipulate the RNG. First of all, there is a grace period where you can't get encounters for a certain # of steps. This is huge because this will stop the RNG from advancing until the grace period is over. Outside the grace period, the RNG is advanced every step until you get a battle. The important thing here is how the game determines when you get random battles. It gives a certain random battle when you hit a certain RNG value. This gives you a way to advance the RNG a set amount (random battle to random battle) with some precision. As of right now I don't know exactly how the RNG is calculated or what values are important. If you want a certain RNG that takes too many battles to reach, you can advance it by spending time on a screen with an NPC. Since the RNG advances so fast with an NPC on screen, what I do is I enter and exit a building a certain # of times to advance it. This lets me be relatively precise with it since the movement is always be the same which means the time spent on that screen should be the same.

The most notable use for this is the Wheel. I actually demonstrated an RNG manip using this on my stream. I'm too lazy to link right now but check the past broadcasts for 9/29 and it should be there. I hit 1st try wheel consistently using RNG manip once I figured out what I needed to do.

Another thing that might be manipulable is Tai Ho. The RNG advances every frame that you are on the Chinrochin screen which makes manipulation difficult. However, it seems like you may be able to control his first roll before the RNG changes too much. So if you find a manipulation that gives 1st roll Tai Ho then you might be able to figure out where you are in the RNG afterwards despite how fast it changes. Theoretically, you can hard reset in Great Forest, get 1st try 6x Kobold, get 1st roll Tai Ho, adjust your place in the RNG using random encounters in Toran Castle, and get 1st try wheel. However, someone would have to find the right RNG manip for this and emulator ends up different from PSN/PS2 so it would be really difficult to find.

Anyway, I'm gonna go to bed now. I have some more information that I'll try to put up later too. I still have a lot to figure out but hopefully you guys can help me with this and we can break this game!

Tilmandra and Seya27 like this
California, USA

Holy Rune manipulation example.

Wheel of Misfortune example.

Both taken from a mediocre run so no real explanation. I can't explain the Holy Rune one too well but the Wheel I understand really well so let me know if anyone wants me to type some stuff up on that.

Seya27 likes this
California, USA

Don't know what happened to the vids but you can check my YouTube for more vids of the manipulation. And I have a link to a Google Drive folder with notes in my Twitch bio. You should be able to get to both through the little links to the left of my reply.

California, USA

Keep in mind this is all for the PSTV version and probably won't work for other versions. Here's a video of an easier RNG Manipulation for Holy Rune. Only the movement after loading the save matters. And the movement inside the house doesn't matter either. Just make sure you re-enter your house the same amount of times and the amount of steps you take in Greminster is the same. You don't have to path exactly the same in Gregminster, just make sure the step count matches. Also, never stop moving in Gregminster.

As for Marco, on PSTV whenever you talk to him the RNG value resets to 0x12. This let's you predict what cups the coin is going to be and what RNG you'll be on after. Here's the pattern for the first 15 cups PSTV. 222 221 121 211 311 (1 = left, 2 = middle, 3 = right). Assuming you play the same amount of games and have the same movement leaving the town you should always get the same battles after.

If you need anything cleared up better just let me know.

Decapent316 and Tilmandra like this
Norway

^ i tried the holy rune manip on emulator, and it worked there too, just coincidence you think zero?

Oh and stallings, was very helpful for me to watch more or less most of z3r0's run on https://www.twitch.tv/z3r01337/videos/all to learn how he walked and whatnot, takes some practice!

Edited by the author 6 years ago
California, USA

Wait really? What emulator? And any info on game version would be nice. I doubt it's coincidence. But I'm pretty sure I've tried it before and failed. So I'm thinking maybe PSN version of the game is just a different version of PS1 Suikoden ISO. As far as I know there's 2 versions, 1.0 and 1.1.

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