About Kingcoin

Kingcoin is a simple (yet fun) game of chance involving the spinning of a colorful wheel. Every game is different because the sizes of the colored slices are randomized for every game. Win by matching a variety of color patterns over a sequence of spins! You can play for free by wagering "points" or, to make things more interesting, you can sign in to wager real bitcoins. Kingcoin believes in transparency and fairness when it comes to online gaming, which is why all of the chance events that occur within the game are generated to be "provably fair". See below for a description of the details, but in essence it means that we're not "cooking the books" — otherwise, you'd know. Kingcoin borrow Bitzino's innovative method for proving that every game is fair.


How do I know Kingcoin is fair?

Kingcoin uses Bitzino's method to prove that we're playing fair. But Kingcoin uses a spin wheel rather than a deck of cards, so we had to modify the method to work for us.

In Kingcoin, we have to prove that both the division of the wheel into slices is fair, and also that the spins of the resulting wheel are fair. To prove that the division of the wheel into slices is fair, we represent the wheel as a string of 0s and 1s. The 1s mark the boundary between two slices, and the number of 0s in each resulting chunk define the size of a given color slice. The order of the slice colors is B (blue), R (red, Y, (yellow), and G (green). So, for example,

describes a wheel where the B, R, and G slices are of equal size (each represented by 3 0s), and the Y slice is about 3 times as large (represented by 8 0s).

The black slice is a constant 16% of each wheel and is not involved in the above representation.

The King slice is a constant 1% of each wheel and is also not involved in the above representation.

When it comes to spinning the wheel, the wheel is represented with the numbers 0 (blue), 1 (red), 2 (yellow), 3 (green), 4 (black), and 5 (purple). The above wheel would therefore become:

Note that 4s and a 5 have been added in the above representation to represent the black slice and the purple slice of the wheel, which is a fixed 16% and 1 of the total wheel for each game. Note that the purple slice in this example is more than 1%

The above representation of the wheel is shuffled using the Bitzino method to determine the outcome of the game in a provably fair manner.

What is the expected value of Kingcoin?

On average, a 1 BTC bet will pay 0.957. Of course, you are way luckier than average, aren't you? :)

I'd like to simulate the game myself to calculate its expected value. What are the parameters I need to know?

Analysis of Kingcoin is encouraged. Note, though, that as the game evolves, its parameters will change. There will always be clear and obvious notice given on the main page when this has happened.

The wheel is represented by a 1000-character string. Each character represents 1/1000th of the wheel and is either 0 (for blue), 1 (for red), 2 (for yellow), 3 (for green), 4 (for black), or 5 (for purple).

(The 1000-character string is revealed to the player after the game completes (as part of the fairness provability). See the "final spin outcomes" field in the "Provably Fair" secion on the main page.)

The wheel is subject to the following constraints:

  • The black slice is always a fixed 16% of the wheel.
  • The purple slice is always a fixed 1% of the wheel.
  • The other slices (blue, red, yellow, and green) are of a random size each game (but fixed during each game) are each at least 15% of the wheel.

The 1000-string is shuffled in a provably fair way, and the first 5 characters represent the outcome of the game. Note that because of this representation of the game, it is technically impossible to hit precisely the same point on the wheel more than once.

Are the free games the same as the games where real bitcoin is bet?

Yes, whether you play for points or real bitcoin, the game works in exactly the same way, so your chances of winning are exactly the same.

Why do you show a history of the last 100 paid games?

To be more transparent. Showing a history of the last 100 paid games allows the Kingcoin community to examine and analyze outcomes of games and payouts in aggregate. As Kingcoin grows, we'll show more history; our goal is to eventually log and publish every Kingcoin game.

How do I send money to my Kingcoin account?

After signing up for an account you'll be given a bitcoin address to which you can send money to fund your Kingcoin account and allow you to play the game for real bitcoin. If you'd like to top-up your account, click the "Add bitcoin" link and you'll be shown the bitcoin address to which you should send your bitcoins. Of course, you'll need to use your favorite bitcoin wallet to send money to your Kingcoin account.

How do I cash out my winnings?

Simply enter the number of bitcoins and your bitcoin address in the text fields below the wheel. We'll deduct a small transaction fee (paid entirely to the network; Kingcoin keeps none of it).

Why can't I withdraw my full bitcoin balance?

You can, as soon as we receive at least 1 confirmations on your balance from the network. It usually takes around 5-10 minutes or so to get six confirmations.

Why does Kingcoin say I'm "low on confirmed funds" and prevent me from playing?

When you deposit bitcoin into your account, we let you play with some of that bitcoin before we get any confirmation from the network. This lets you play a little immediately without having to wait. However, you can't plaYou can play with the rest of the bitcoins only after we get at least one confirmation.

Say you have no bitcoins in your account (as in the case of a brand new account) and you deposit 5 BTC. The 5 BTC will show up in your Kingcoin account almost immediately, before we've got a confirmation. However, your "confirmed balance" will remain 0 until we receive confirmation of your deposit. You'll be able to play with a portion of the deposit immediately.

I have a great idea to make Kingcoin more fun.

Great! Do email us and let us know.


Email me! I'll respond.

Sanjay Mavinkurve