Fixing a broken emission curve

3 min readMay 20, 2019

Correcting the last of the inherited code base

The emission curve for Ryo was one of the final aspects of the code we inherited that has not yet been re-written. Many community members over the last year had been pushing us to modify the curve. When we looked into it, we found code that in no way resembled the advertised emission curve. This article will explain what we found, and how we fixed it.

Total Supply

The advertised total supply is 88,888,888 coins before tail emission. When we burned the premine, we permanently removed 700,000 coins from the curve for a total planned emission of 88,188,888 coins. The existing code, however, hits 2,102,393 coins short of the intended target. That’s about a 2.4% difference. The modified curve will hit the intended target exactly when tail emission kicks in.

Post Peak Block Rewards

After the peak emission, block rewards start to drop. The emission curve was always advertised as changing every six months. The existing code, however, has a smooth decline in block rewards that decreases every block. The modified curve corrects this, and block rewards will change on six month intervals as intended.

Tail Emission

The tail emission was advertised at four coins per block. The existing code, however, had a fixed emission of four coins until those extra 2,102,393 coins were generated, then dropped to the true tail emission of two coins per block. The modified curve has a tail emission of four coins per block as intended.

The Modified Emission Curve Details

The modified curve (in blue above) was created with lots of input before two rounds of community debates. The final curve brings forward the peak one and half years, and extends the peak into a year long plateau. To account for the lower top block reward, the decline portion of the curve is drawn out and decreases by 6.53% every six months.

This modified curve accomplishes a few points. It keeps the fundamental idea of the camel emission where the highest block rewards are not at the start of the chain. Block rewards will be higher than they are today for the next 3.5 years, and will have been higher than the initial block reward for 8.5 years from the genesis block. This emission curve is what makes Ryo a more fairly distributed coin than most other cryptonote coins that emit half the supply in little over a year.

The modified curve will take effect in just about one year from the date of this article. That amount of time was purposefully chosen in order to make the change gradual instead of sudden.