[9,000,000 token reward]Mining Competition Round 4 is here!

With the third round of the Nervos CKB mining competition completed, we want to express our sincere gratitude to the community, and all that participated. Not only did this round help us further stress test the network and provide valuable data and insights, but the community also helped us identify a bug which is now being fixed!

To reward our community for participating in the construction of Nervos CKB, the Nervos Foundation is sponsoring the fourth round of the CKB testnet mining competition! Anyone can participate in the testnet mining, and potentially win a total of 9 million mainnet CKB tokens. Please join our Telegram(EN) if you have any questions

The goal of Round 4 of our testnet mining competition is to test our new hash function— Eaglesong, here is RFC and introduction.

Eaglesong is the hash function for Nervos CKB proof-of-work, already deployed on testnet. Also we have Eaglesong’s GPU miner, which you can check on GitHub.(please note that as our resources are limited, the GPU miner is only for Nvidia GPU, and we are working on AMD GPU miner now. The Nervos team has no preference over Nvidia or AMD GPU.)

After the third round of our mining competition, we released RFC (Request for Comment)to ready us for the fourth round. We gathered comments from our community members and adapted the rules as follows:

Reward distribution

Total rewards: 9,000,000 CKB main net token

Reward distribution:
All addresses that have mined at least 1,000 CKB will share this rewards pool and receive CKBytes in proportion with the block rewards produced by each address.


Start: September 7th 6:00 AM (UTC) UNIX Timestamp: 1567832400
End: September 21th 6:00 AM (UTC) UNIX Timestamp: 1569042000

Competition Process:

9.7 5:00 AM UTC, release CKB testnet v0.20.0 in Github. ONLY using this testnet version can participate in mining competition.
9.7 6:00 AM UTC, competition begin. Blockchain explorer will be ready in two hours.
9.21 6:00 AM UTC, competition is over. We will release the result within one day on this website.

How to participate

To start mining on CKB testnet, simply follow the steps outlined in the official guide or community-created tutorials on Nervos Talk. A CKB blockchain browser is also available to look up your mining rewards.

CKB-Mine-Lord website created by our community member to show the rank of all the addresses, you can check it to get your real-time rank, here isthe code of this website for your reference.

Upon the completion of the competition, we will calculate block rewards mined by each address. The accumulated block reward of each address during the competition will form a basis for CKB mainnet token rewards (testnet tokens gained by transactions will NOT be counted as block rewards).

Rewards will be distributed directly to respective addresses on CKB mainnet. Please exercise caution when managing your private key as it will be your sole means of claiming your CKB token rewards.


  • How are the block rewards in CKB different from those in Bitcoin?
    • For Bitcoin, the block rewards are fixed in each block you mine; For CKB, the total block rewards are fixed in each difficulty adjustment epoch. CKB consensus adjusts difficulty to adjust block time, when difficulty increases, there will be less blocks mined during one epoch, but block rewards in each block mined will be increased. And vice versa.
  • What is difficulty adjustment epoch in CKB?
    • On the current Nervos CKB testnet, we target difficulty adjustments at every four hours (In Bitcoin, the difficulty adjust happens every 2016 blocks, while the block interval is 10 mins). For more details please refer to our consensus RFC.
  • Why do the rewards only apply to addresses that mined at least 3,000 CKB testnet token ?
    • The native token CKByte represents state storage space on the Common Knowledge Base blockchain. A cell is the basic data structure in the blockchain, and you can put any arbitrary data in a cell. It requires 60 CKBytes to create a cell.
    • During mining competition phase ONE, 105,000,000 CKB testnet token were mined, and we expect the same amount of testnet token will be mined in round 4. Given the rewards of 9,000,000 CKBytes, it requires you to have at lease 700 CKB testnet token mined to be able to receive the 60 CKBytes rewards. We add some buffer and require at least 1,000 CKB testnet token to receive rewards.
  • After mining a block, how long does it take to receive the block rewards?
    • The block rewards from Block N will be received in Block “N + 11” (about 3 minutes) via Cell Base Transaction. This design related to our two-step transaction confirmation, if you are interested please check our consensus RFC .
  • What is Eaglesong? Any Eaglesong miner available?
    • Eaglesong is a new hash function developed specifically for Nervos CKB proof-of-work. It is also suitable in other use cases where a secure hash function is needed. The design criteria were exactly those described above — novelty, simplicity and security. Here is the article written by the designer Alan and the RFC.
    • Also now we already have miner. But it only support Nvidia Card. Please note that for now, the Nervos team is working on Layer 1 CKB. As our time and energy is limited, the GPU miner is only for Nvidia GPU. The Nervos team has no perference over Nvidia or AMD GPU.
  • How to know the value of token?
    • There’s 33.6 billion CKBytes mainnet token in genesis block ,more info you can check our token sale update.

Things to Note

  • This is the fourth round of competition in a series. We may have future rounds and may change the rules.
  • In the previous round, some rewards are distributed to null address, which may caused by entering the wrong Lock Args. So please make sure everything is right when you are configuring.
  • CKB tokens rewards will be sent to the corresponding address when mainnet launches. Please keep your privkey safe to get the reward.
  • Addresses for the same private key might be different on testnet and on mainnet due to difference in algorithm. Participants only need to hold on to their private key to be able to claim rewards.
  • Participation in this event means that you have read and understood the competition terms.