How to play the Dice in SouthXchange

SouthXchange
6 min readMay 9, 2019

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SouthXchange has a simple but fun Dice game. Learn how to play it and win!

Full dice game

The concept of the game is very simple: you roll a 100-sided virtual dice and you bet that the number that will come up (called the rolled number) is lower than a given number of your choice (called the target). For example, you can bet that the rolled number is going to be lower than 60. If the rolled number is 56, you win. On the other hand, if the rolled number is 72, you lose. Your freedom to chose the target number allows you to play in a risky or conservatively way. For example, if you choose the target 90 then your chances of winning are high (i.e. there are high chances the rolled number will be lower than 90), but if you choose the target 10 then your chances of winning are low.

Aside from the target number you must also specify how much you bet. If you lose, you lose this entire amount. If you win, your bet is multiplied by a number that is inversely proportional to the chances of winning. In other words, the lower chances of winning, the more you win. This is called the multiplier. Here you can see some multipliers based on some targets:

Some multipliers depending on the target

For example, let’s suppose you choose the target 50 and you bet 0.1 BTC, which is the entire amount in your account. If you win, your bet of 0.1 BTC is multiplied by 1.98X (i.e. almost double) and your account balance ends up being 0.1 x 1.98 = 0.198 BTC. Behind the scenes what happens is that, since you already have 0.1 BTC in your account, the game will credit you the remaining amount (0.098 BTC). On the other hand, if you lose, you will lose your entire bet of 0.1 BTC.

How to play

There are two flavors of the game: the full dice and the quick dice. First we will see the full dice.

Before rolling
After rolling
  1. Choose the coin. There are about a dozen coins that can be used for playing.
  2. Enter the amount to bet or move the slider. You can bet 0 just to try the game, and nothing will happen if you win or lose. You can also grab some free coins from our faucet if they are available (green button labelled 2a). There is a maximum that you can bet and it depends on your target (see step 4). Essentially you cannot win more than what it says in “Max win per roll”.
  3. Roll. Here you ask the system to roll the 100-sided dice. A random number between 0 and 99 will come up but it will be hidden. You will see the hash of this number in the lower section on the left (see below for a technical explanation). Once you roll you have 30 seconds to bet.
  4. Select your target. Move the slider to select the target. Alternatively you can click the buttons with pre-selected targets in section 4a. Your prize will depend on how much you bet and this target.
  5. Bet. If you used the slider to select the target you must click the Bet button to bet. If you used the pre-selected targets in section 4a you will be betting as soon as you press these buttons.
A winning result

After betting you can see the result (win or lose). Also the system will automatically roll the dice again after you bet, so you can quickly bet again if you want.

What about the quick dice?

There is a simplified version of this game called quick dice. It is always visible in SouthXchange and it is located right above the searchbox on the right.

Collapsed quick dice

The idea is the same: you roll and then you bet against the rolled number.

Quick dice after rolling

It is the same game but you are limited on the options for selecting the target: you must use one of the pre-selected targets. Also you cannot choose the modifier: it will always be 0 (see provably fair section below).

Is this game provably fair?

You may be wondering how you can be sure that the system is not cheating by choosing big numbers (i.e. close or equal to 99) most of the time. The answer is the modifier in the lower left section of the screen. This modifier will be added to the number that comes up in the dice, and this will be the final number that you bet against.

You bet against the generated number plus your own modifier

In the example above you can see that the dice rolled the number 12 but the modifier was 18, so the final number is 12 + 18 = 30. The rolled number is fixed when you roll (you get the hash as soon as you roll), but you are free to change the modifier at any time before betting. Even if the system is “cheating” by always rolling large numbers, you can enter any modifier of your choice to change the number. Since there is no way the system knows what number you will choose for the modifier, the game is provably fair.

How to verify the rolled number with the hash

The rolled number is actually part of an alphanumeric string of several characters that always ends with a number between 00 and 99. This last number is the actual rolled number. In the example above the rolled string is 2jh8O78YI35w35i6MN46e2sbny1S7512 and the rolled number is the last two characters (12). When you roll, this rolled string is not shown but instead you get its hash (SHA-256). After you bet, this rolled string is revealed and you can hash it to make sure the number was not changed.

In the example above, we received the hash 9cdb3be8804b394979842926f33b5aa62e17b8109c1e7e50e5d486c92c33c737 as soon as we roll. After betting, the rolled string 2jh8O78YI35w35i6MN46e2sbny1S7512 is revealed. You can use any online SHA-256 hasher (e.g. this one) to verify that the hash of the rolled string is what we received when we rolled, thus proving the rolled number was generated before the bet (and it could be modified by us using the modifier):

Hash verification

Conclusion

At first the game may seem complicated but in reality it’s very simple. Just give it a try and you will see! Feel free to use the free coins from our faucet to experiment.

Good luck!

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