About Trading

[hidari_hand]

Here we can try discuss about this side of game mechanic more seriously so we can make the simplified (if possible) and the ultimate guide for Suikoden II Trading.
Feel free to discuss the revealed mechanics of trade or the hypothesis or the not yet revealed mechanics about this topic.
I can't do it without your help.
Thank you in forward.

>Guide
Item, where to buy, where to sell
In parenthesis: The higher change that it is a right time to buy/sell when the quantity higher/lower than that value.

1. Must Buy/Sell item.

Ancient Text, Kobold Village, Forest Village.
Mayonnaise, South Window City, Kobold Village.
Crystal Ball, Any City, Kobold Village.

2. Watch The Quantity Carefully (HELP ME TO EXPAND THIS SECTION)

Sugar, Forest Village (28), Kobold Village (9)
Wooden Amulet, Kobold Village (6), South Window City (0)

>Discussion about General Mechanics:

1. Idle Shop - The shop's system that runs without player's interference
a. The Price and The Quantity Recalculation
-Every 5 minutes on Kobold Village (by hidari_hand 4/28/15)
-Every 15 minutes on South Window City (by Omnigamer 5/2/15).

what does it mean: It means that every 5 minutes or 15 minutes, the quantity which followed by the price of certain item in certain trading post will change its value.

b. The Max/Min Item Quantity
- Fix for each item in certain trading post (by Omnigamer 8/26/14) (confirmed by hidari_hand 4/28/15)

what does it mean: It means that the quantity of each item is lock on certain pattern.
e.g : The quantity of sugar in Kobold Village that allowed is 11 for the highest value or 9 for the lowest one whereas
in Forest Village is 28 for the highest value or 23 for the lowest one.

c. Final Price Regulation.
- Good Price follows certain rules

Rules that proposed by Omnigamer 4/29/15
Good Price = Max Price/(stock^2)
Good Price = Max Price/stock; if stock = 0, then Good Price = Max Price * 2

in exception (by Antimatzist 4/30/15)
Mayonnaise, in Highway Village.
Flute, in Kobold Village

Addition Rules that proposed by Antimatzist 4/30/15
Good Price = Max Price /(x-1)
For items with low stock = 0 and max stock = 1, the ratio between both prices equals to 1.5, 2 or 2.5.

2. Working Shop, The shop's system that runs after player's interference
-Still unpredictable.

3. Story line dependence.
-Might be depends on main story line (Omnigamer 5/2/15)

[Omnigamer]

Please see what I wrote in this thread:

http://suikosource.com/phpBB3/viewtopic.php?f=9&t=13874

The major point is that trading prices are binary, and vary between two sets of numbers with a random number (0~9) added on afterward. There's a 50-50 shot that any given item's quantity/price will be one or the other on any given visit.

[hidari_hand]

Please see what I wrote in this thread:

http://suikosource.com/phpBB3/viewtopic.php?f=9&t=13874

The major point is that trading prices are binary, and vary between two sets of numbers with a random number (0~9) added on afterward.

I've actually hahaha..
but scanning through your excel data (the upper limit and lower limit)

I found some lower data that is even lower than your lower data or even higher than your higher data.

so after all 11 samples not enough, I think..

[Omnigamer]

Could you provide some examples, along with what point in the game you are at? The only missing info is if the numbers fluctuate based on story events. I am quite confident that the system works as I described, though, with only 2 possibilities for each good at each location for a given point in the story.

[hidari_hand]

Could you provide some examples, along with what point in the game you are at? The only missing info is if the numbers fluctuate based on story events.

for example
your data:
Kobold Village
Sugar 320 320 314 316 384 382 388 381 311 319 388
Ancient 1168 1171 469 464 468 1170 1161 1166 1161 1168 472

SWC
Blue Dragon 15999 15997 16005 16004 16004 16005 15995 15996 16001 16005 16004

Forest Village
Sugar 130 136 135 160 167 132 161 157 167 163 159

mine:
Kobold Village
Sugar 373 382 116 213 174 161 175 180 244 277 380 385
Ancient 1050 701 704 1168 1048 878 832 795 752 725 (463) (578)
*numbers in parenthesis are ancient's prices when it have 1 quantity. I'm sorry. my bad.

SWC
Blue Dragon 16004 8000 15996 16000 16001 16004 16004 15999 16003 15997 15994

Forest Village
Sugar 158 172 178 175 174 174 174 161 163 159 159

NB: no story line progression (after Luca's death and before meeting Culgan in Kuskus), the quantity of each item constant (constant in all sampling, sugar constant at 20, ancient at 0, blue dragon urn at 1).

And also, I think there's a chance for sudden price discount.
Like in SWC sampling no 2. when suddenly every tradeable item had 50% price.

[Omnigamer]

What do you mean by "quantity is constant?" If you are trading stuff to equalize the values, you are influencing the trade prices that way as they regularly recalculate at intervals faster than full shop refreshes. My data was entirely from "fresh" visits, with no prior trading or otherwise.

[hidari_hand]

What do you mean by "quantity is constant?" If you are trading stuff to equalize the values, you are influencing the trade prices that way as they regularly recalculate at intervals faster than full shop refreshes. My data was entirely from "fresh" visits, with no prior trading or otherwise.

It's one of my control variable. And..
Nope, I don't do that. Just examination, no trading. just "fresh" visit

Weird doesn't it? maybe there's another variable that I missed

Statistically, your finding and mine have similar range, maxima, minima, mean.. etc. only minor or slight difference.
like what I've found with blue dragon urn which is similar with yours except that 8000 which as I've said, suddenly became 50% on all items.

btw, if we trade mayonnaise from south window to kobold village,.. in high confidence, we'll get profit
on the other hand, trading salt from south window to forest village is very risky.

[Omnigamer]

I'm still fairly certain that my comments on the system are accurate and that any case of "fresh" shops will have only one of two prices, determined by quantity and potentially story events. In that case, no amount of statistics on the values particularly matter. I cannot explain the "middle" values you observed since I don't know your complete experimental setup. I will do some digging in the code soon to confirm.

For consistency, can you also remark on which version of the game you are playing? PAL, NTSC-US, NTSC-JP, I+II Collection, etc.

[hidari_hand]

I'm still fairly certain that my comments on the system are accurate and that any case of "fresh" shops will have only one of two prices, determined by quantity and potentially story events. In that case, no amount of statistics on the values particularly matter. I cannot explain the "middle" values you observed since I don't know your complete experimental setup. I will do some digging in the code soon to confirm.

For consistency, can you also remark on which version of the game you are playing? PAL, NTSC-US, NTSC-JP, I+II Collection, etc.

it's NTSC-US

About the statistics, it's just my approaching method because I can't do coding nor understand the principle of coding.
But in my defense, with this approach I can really sure what and where to trade items without bothering the 50/50 change of high and low demand state. Just as my intention to make a simplified trading system with 100% guarantee of profit hahaha..

About my method (summary),
visit one trading post,
check item quantity (if it have my control quantity, I'll continue to the next step),
check its price,
move to next trading post.
and if I may, what's yours?

Next, I have a hypothesis.
Are there any chance that other item quantity will affect the other one?
Like, when I visit kobold village (KV) for the first time.
Ancient text's price is 1xxx when 0 quantity.
after that, on my second visit to KV.
Ancient text's price is 7xx even when its quantity is 0 but maybe because sugar is in low demand state.
So It also alternate Ancient text's fate as "low demand of high demand" state?

Because the only thing that I missed is the other item value which not my observation object.
Except that 8000 which all item have 50% of its original price.

I'll observe with complete item value in certain trading post
and let's elaborate our finding some more..

[Omnigamer]

My testing was done by saving prior to checking a particular post, checking, and then reloading and repeating until I had collected sufficient samples for that location.

The way that trading posts are initialized is as follows:

-Every time the game timer hits a multiple of 30 minutes (eg, 1:30, 4:00, 23:30), all shops in the game are "reset." For most shops, this just means Rare Finds are set to unitialized, but for Trading Posts the whole inventories are set as uninitialized.
-The shops remain uninitialized until you talk to the shopkeeper, during which time the Rare Finds and trade items are enumerated via the game's random number generator. Once enumerated, they remain "locked" until the next point in the game time that everything is reset.
-Trading posts may have times where they recalculate their stock periodically to account for items you have bought or sold. I don't know the exact mechanism for this; my guess is that it happens every 15 game minutes or so. This is different from resetting in that the stock shouldn't change as a result of the recalculation, only the price.

Based on your methodology and results, there may be some global influence since you are initializing multiple shops in one time period. For example, initiating KV and FV may do some checking against the global supply of a good instead of just the local supply. This complicates things a bit more if correct. I do not believe that non-equivalent goods affect each other however; the quantity of sugar should never affect the price of Ancient Texts or vice versa. That is, unless it is another of the game's many bugs.

[hidari_hand]

Recent study conclude that every 5 minutes after last dialog initiation of the npc, the price and the quantity of tradeable items are changing and each trading post has its own "time counter". The quantity and the price follows Omnigamer's previous study conclusion (http://suikosource.com/phpBB3/viewtopic.php?f=9&t=13874).

How to reproduce this finding.
1. initiate dialog with the npc on certain town.
2. Write down all the quantity and the price.
3. Quit the dialong and start the stopwatch
4. Check the quantity and the price,
every 1 minute for 10 times,
then every 2 minutes for 5 times,
then every 3 minutes for 4 times,
then every 4 minutes for 3 times,
then every 5 minutes for 3 times.
5. Done the same thing on different trading post npc.

Result being expected.
1. After 1 minute up to 4 minutes, there's no changes in quantity and price.
2. After 5 minute, the quantity and the price is changing.
3. When "time counter" in npc A already 5 minutes but in npc B doesn't, only npc A change its item and price value.
4. When "time counter" in npc A already 5 minutes and also npc B, both will change its item and price value.

[Omnigamer]

That's pretty significant if it recalculates every 5 minutes. Just to clarify, you're saying that the quantity and prices vary according to the high/low-stock system I describe every 5 minutes? If so, that could lead to some very abusable short sales of certain goods, where you buy and sell to the same trading post for a guaranteed profit. If they're using some variety of divisor for determining current good price based on stock, you could definitely buy some of the goods with a lot of stock up to a "break even" point, let it recalculate, and then sell back for profit regardless of whether it recalculates as either high or low stock.

[Omnigamer]

A couple more observations from my recent playthrough seem to confirm that the high stock is at least influenced by story elements. On the first trip to South Window, Coral has a stock of either 0 (53333) or 1 (26666). In my testing of shops close to end-game, the high-stock value was instead 2 (13333), never 1.

Some things to note about the prices. The max demand price is ~53333 for no quantity available. When quantity is 1, price gets cut in half. At quantity 2, it is 1/4 of the max value. This probably isn't consistent across the board (I haven't gone out of my way to run numbers on other goods), but this leads to a couple thoughts:

1. Good Price = Max Price/(stock^2)
Pretty sure this isn't correct. It's consistent with the current example, but the price drops pretty drastically the further the stock goes. This would make goods with typically a lot of stock (20+) incredibly valuable if you buy all of them and then force a recalculate.

2. Good Price = Max Price/stock; if stock = 0, then Good Price = Max Price * 2
This seems much more plausible, but again, I haven't tried to apply it to any other goods. Basically just means that good prices have fairly minimal variation as they have more stock (a divisor of 20 isn't all that different from a divisor of 30), but would again make goods very pricey if it recalculates against any 0 stock.

There may be other ways it is calculated, but this is all just conjecture based on a single case. This also depends on the logic for recalculating: if it always restocks according to the High/Low Stock model, this isn't terribly useful. If it recalculates based on current stock, that's something else entirely. Either way, it's worth playing around with it a bit more.

[Antimatzist]

I did some testing with your excel sheet and... it's confusing.

Some items follow the rule Price(x)=Baseprice/x, with the base price being different for every location. Sugar follows this rule everywhere, for example. Musk as well 8with some slight deviation, probably rounding errors or something).

But some items follow this rule at some places, and not at others. Mayo e.g. does follow this rule, but not in Highway. Some other items follow a rule like P=baseprice/(x-1) (Mayo, in Highway, Flute in Kobold)

For items with low stock = 0 and max stock = 1, I often find that the ratio between both prices equals to 1.5, 2 or 2.5.

[Omnigamer]

Could you further remark on your testing methodology, hidari_hand? I was not able to reproduce your results for a 5 minute interval; the smallest update interval I uncovered with some basic testing was 15 minutes. I tried:

-Talk to SW trader NPC, check wares, close dialog and wait 5 minutes.
-Repeat of above with also exiting the trading shop inbetween checks.
-Repeat of above with exiting SW to World Map.
-Repeat of above with longer timeframe (10, 15 min).

I could only get the prices/quantities to update in total intervals of 15 minutes or more.

Something to note: I tried to manipulate prices during some of the checks by buying all stock and seeing the restock behavior. To note is that good prices for items with typically only 0 or 1 stock did not fluctuate greatly after a recalculation. Specifically, the price only increased across 4 different items by about 1000 potch over the normal 1-stock price. This means that trading, at least in terms of short sales back to the same shop, gets a lot more complicated as it looks like they put in place some measures to prevent it. Probably the quickest way to get to the bottom of it is to actually go and start picking through the code. Unfortunately it's not a huge priority for me right now since I don't need trading for any% runs, but if I get a sudden rush of motivation sometime I can dig through and pick out what's up. Some things that I think are currently understood though:

-Initializing the shop has consistent sets of goods/prices.
-Subsequent visits to shops that have already been initialized follow different quantity variations than the initialization.
-Influencing prices by buying or selling goods has a somewhat unpredictable effect when the shop recalculates.
-Shop initialization values are influenced by Story events, and possibly other shops.