Once you've researched Blackchain (or if you already have blackcoins), blackcoins can be bought with relics. Blackcoin speculation is all or nothing: clicking the "buy bcoin" button will use all your relics; similarly, clicking the "sell b-coin" button will sell all your blackcoins. Blackchain is unlocked by Quantum Cryptography
Games started after July 20th 2026 will default to HODL mode. it can be disabled in the options menu.
When "HODL mode" is enabled the price of blackcoins will be based on the real-world price of bitcoin.
The price of blackcoins starts at 1000 and will fluctuate slightly daily. There is a 40% chance that the price will increase, a 30% chance that the price will decrease, and a 30% chance it'll stay the same.
Each game day, if the price does not stay the same, then the game generates a uniform random variable in [0, 0.0025%), and increases / decreases the price by that percentage.
Therefore, each game day, the change in ln(blackcoin_price) has mean +1.249 927e-6 and variance 1.442 706e-10.
If the price ever exceeds 1100 the market will implode and the price will drop drastically, but will continue as normal from there.
After a market implosion, the price will be in the range [770, 880.022).
If you always sold blackcoins immediately before the market implosion, then bought immediately afterwards, on average you would multiply your relics by e (≈ 2.718 281 828) approximately every 800 000 game-days; equivalently, you would double your relics approximately every 800 000 * ln(2) = 554 500 game days or 12 days 20 hours in real life.
The price of blackcoins is kept across resets.
With the Invisible Black Hand upgrade, there's a new "Annoy the Invisible Black Hand" button that immediately causes a market crash. It costs more the lower the B-coin price is. This is useful if B-coin price is close to 1100 and you're about to leave for a while. Just sell your B-coin, Annoy the Invisible Black Hand, and rebuy. Then the market won't crash in your sleep.