Orphan, Uncle & Genesis Blocks??

Let’s break it down –

Did you think a block was a block was a block? Actually, in the cryptocurrency and blockchain space, there are several different kinds of blocks. Although not everyone understands what they are nor what they mean. Hopefully, by the time this article is read and absorbed, the reader will have a better understanding of the different block types and the functions each serve within blockchain-based protocols.

Blocks in Bitcoin blockchain:

  • The Genesis Block begins the blockchain.
  • The (Valid) Block is a block that gets included in the Bitcoin blockchain. A miner that finds it gets rewarded.
  • The Orphan Block is a block that doesn’t have a predecessor/parent. Miners don’t get rewarded for orphan blocks.
  • The Stale Block (Orphan’s offspring) is a block that doesn’t get included in Bitcoin blockchain because an orphan block precedes it. Miners don’t get rewarded for stale blocks either.

Genesis block – Providing the foundation for every blockchain-based protocol is the Genesis Block. The Genesis Block is the FIRST block on which the entire blockchain is built. The creator of Bitcoin left a message on Genesis Block that reads: “The Times 03/Jan/2009 Chancellor on brink of second bailout for banks”. It seems fitting words for the Genesis Block of Bitcoin; however, its interpretation is undoubtedly open. A Genesis Block is the first block (block number 0) in a blockchain and is the only block in a blockchain that does not have a valid reference to a previous block. The Genesis Block has no transactions.

Orphan Blocks were valid blocks that met all the requirements to be added to the blockchain but still rejected. Why is this? Orphan Blocks occur when two or more miners produce a block at similar times. Latency can be an issue, especially if the miners are vast distances apart. Nodes serving the area closest to the miner will pick up this miner’s submission that is closer to them. In these cases, the miner with the most “proof of work” wins the reward, and the other block(s) become “Orphan Blocks.” How often does this happen? More times than some care to mention.

Blockchain.info keeps track of all the orphaned blocks, and they show this occurs as often as one to three times daily. Since a new block is mined on average every ten minutes, and 144 block rewards paid out daily, this would also mean that Orphan blocks happen over 1% daily.

It is not the block that is orphaned

These “Orphan Blocks” topics are confusing because of the wording, even for seasoned Bitcoin miners. This incorrect terminology likely began because these “stale blocks” referred to as orphaned blocks in the Bitcoin reference client. In actuality, orphaned blocks are not orphans as they DO have parents in the form of the previous blocks added to the blockchain. What part IS orphaned then? It is the payout that is orphaned.

An orphan block being produced by Bitcoin network
Source: Blockchain.info

From the image above, you can see that two blocks were created and sent to the Bitcoin network on the same date and at very similar times 13:44:19 PM and 13:44:31 PM by two separate mining pools: AntPool and SlushPool. As you can see, AntPool expended more proof-of-work in creating its block, so it is chosen over the block created by SlushPool. Notable, too, is that even though the block is valid according to the consensus rules of Bitcoin protocol, miners don not get the reward for the Orphan Blocks.

Stale Blocks:

Stale Blocks often referred to as “offspring” of Orphan blocks. Most often, when people say “orphan block,” they mean a Stale Block. A Stale block is a well-formed block that is no longer part of the blockchain. The Block Reward is no longer spendable on the blockchain; therefore, whoever mined that block does not get the reward (or the transaction fees). Often two miners find the “solution” to a mathematical puzzle and submit their blocks to be added to the blockchain at the same time. In this case, the miner with the longest valid chain wins the reward. The one(s) with the least amount of Proof of Work, must discard that block known as a “Stale Blocks,” and resume working on another block.

Blocks in the Ethereum blockchain

Uncle Blocks associated with the Ethereum protocol is equivalent to Orphan blocks on the Bitcoin Network. There is a slight difference, however. Uncle Blocks are still valid blocks created and submitted to the blockchain and rejected by the network. However, unlike the orphan blocks where miners are not rewarded for them, miners DO receive rewards for creating an Uncle block. For a valid block successfully mined on the Ethereum network, miners are rewarded with three Ether. Conversely, the production of an uncle block gives a reward of 2.625 Ether

Ethereum average block-find time is about 14 seconds. Since Orphan and stale blocks are expected to be encountered more often than in Bitcoin networks, miners could waste more time. Thanks to a protocol called GHOST protocol (Greedy Heaviest Observed Subtree) implemented by Ethereum developers, this doesn’t happen. 

The concept of GHOST protocol: Miners who find Uncle Blocks do get rewarded. However, the reward is not as much as for a standard block. In Ethereum and other Daggar-Hashimoto cryptocurrency networks, these blocks are called Uncle Blocks.

Uncle Blocks resolve the problem of network centralization. With the shortened block time, a significant mining pool would work much more effectively and squeeze smaller competitors out. The smaller groups would receive information on new blocks much too slowly and would be creating a considerable amount of useless blocks.

Types of blocks in Ethereum Blockchain:

  • The Genesis Block begins the Ethereum blockchain.
  • A Valid Block is a block successfully included in the Ethereum blockchain. Miners of these blocks get rewarded for their work.
  • Uncle Blocks correspond to Orphan and stale blocks in the Bitcoin network. Uncle Blocks like Orphan and Stale blocks are not included in the main blockchain, and miners get lower rewards for Uncle blocks than for Valid blocks.

Uncle Block Rewards in Ethereum Network

Ethereum will allow seven nested levels of Uncle Blocks, which would be the same as one orphan block and six stale blocks in Bitcoin’s Network. In the Ethereum blockchain, the uncle block reward is figured with this formula:

([Uncle block number] + 8 – [Block number]) * [Ethereum reward] / 8

So, if the normal block reward is 3 ETH, the Uncle reward would be 1/8th less.

The reward for the very first uncle block is 2.625 ETH, for the second one – 2.25 ETH, then 1.87 ETH, and so on until 0.375 ETH. Uncle chains are not likely to go on for very long. After a couple of Uncle Blocks, a miner node will generally abandon the wrong chain and go to the main mining chain.

You can check out Ethviewer to see Ethereum mining. You can see in real-time the main chain and uncle chains being produced.

About the author

Born in Illinois and the third oldest child of 10 children. Gail learned many lessons in life that would serve her well in her future. Patience, sharing, compassion, understanding, love, and acceptance were a way of life. Family is significant to Gail as a mother of three herself.
Gail lives by the motto "live and let live," and she takes pride in helping others. Educated, yes, but believes life is the best teacher and learning depends highly on an open mind.


  1. this is a just incredible to read and then put into my learning curve on how things happen thru out the crypto world and the blockchain and how each coin may be close to an exact replica there are slight or major differences when you look past the headlines — Gail it is with very much appreciation for your effort and continued postings of GREAT Info — thank you — yes this is a multiple times reader —

  2. Learning really never stops, this really has added value to my knowledge and information, the crypto world takes time for anyone to understand but dedication to acquire info is really available for the willing, Gail, thank you and I really appreciate your posting.

  3. Gail, as always excellent information-thank you. It is nice to know we at Compumatrix have someone with your understanding of and depth of knowledge regarding the arena we are operating in, in our administrative leadership. It certainly goes a long way toward helping to assure us of a very bright and prosperous future.

  4. Great post-Gail. The blockchain is the carrier for cryptocurrency. It is exciting to watch your transactions go through the blockchain and finally reach the address you sent it to. When I first starting to sending BTC, I was always on pins and needles until my transaction reaches its destination address. Now if I follow the correct protocol, the blockchain will do its job and deliver your transaction to the correct address. Always double check your address to make sure it is correct. If it is not correct, it is usually gone.

  5. I’m curious! Since so much of this is over my head, I have to ask one question. Regarding the orphan blocks in the Bitcoin Blockchain, are these transactions valid or are they canceled since they are not a part of the blockchain? My curiosity peeked when you mentioned the miners not getting paid for orphan blocks. Or, do they only get paid the transaction fees?

    1. Orphan blocks are not paid out..they are abandoned as miners return to the main chain to resume their work, however, they will remain as detached blocks in the cryptocurrency network.
      Orphan blocks nor stale blocks (“offspring” of Orphan Blocks) are paid.

  6. Well now, here we go again, learning something new every day .I had to read your block chain to try get what you were say Gail to sunk in with me. I read it twice and maybe will have to read it again … I didn’t know there were so many relatives in a blockchain .. Uncle , Orphan on the block chain .. Well this is way over my head and trying to let it sink in .. whether I will need to remember this or not ,time will tell. it is interesting to read .

  7. Thank you Gail, for your posts about the blockchain always make read through a few times to let the information sink in a bit deeper. How wonderful it is to see people becoming more comfortable with using contactless cards rather than loose change in the shops. I imagine all of them wanting to buy a vpc from me. Well done Henry and his amazing team in getting us here and ahead of the game.

  8. The Block chain to me is very complicated structure.I guess that comes from not knowing how it is all put together. It is going to be interesting to watch how the blockchain will be utilized and the world of events and your profile will be embedded and recorded on the blockchain. Times are a changing!

  9. Thank you Gail what an amazing read, I’ll def have to read a few times. It really has to sink in. I’m always amazed at the content here. Well I learned something new again. I never knew there were so many, and they don’t get paid for orphan blocks. Very interesting read. So happy to be under such great leadership. We do have such a great team leading us and we appreciate you all.

  10. Wow….nothing can be taken at face value in the blockchain as there seem to be myriad levels within the structure. I can’t help but feel sad about the orphan blocks that are rejected…not good to compare these blocks to the people orphans! First read this is way over my head, but nevertheless interesting. I won’t ever forget the term orphan blocks, and like Ethereum who have Uncle blocks instead!

  11. The first book of the Bible is Genesis; In the beginning, God created, so I can safely assume that the Genesis block is the first one. Since there are no transactions in the beginning, other legitimate blocks have to be made by generating transactions and are attached to the first block and so on via operations performed to carry the transactions through the system in a fluid method. All these blocks form the blockchain in which all legitimate blocks are attached and transactions from each flow through these legitimate blocks. The Uncles and orphans are not of the legitimate family. I have a vision in my head of a load of containers on numerous train cars traveling down the track. lol lol, I’ll get it.
    Thanks, Gail, this goes in my to-read later file, so I can read again and again.

  12. This is a very enlightening post, Gail, about the Bitcoin and Ethereum blockchains. I learned the meaning the various kinds of blocks. I had never heard of an orphan block or a stale block. Neither had I heard of an uncle block. Obviously the Ethereum network is more sympathetic to miners that is the Bitcoin network. Thank you for this insightful information.

  13. It is very interesting that Ethereum actually pays miners for Uncle blocks. I wonder if that will continue with the 51% attack they just got, and that makes 2 in a week! Sounds like someone is trying to make Ethereum’s life hard!!

  14. I agree with Carmen, the Bible begins with Genesis so it will be easy to remember that all blockchains begin life as a genesis block too. It is all so amazing how this was thought out and put together. We are witnessing humanity changing in about every aspect of our lives. How exciting is that!!

  15. Very interesting how the bitcoin creator named the first block Genesis and left the bank bailout message I think that was a hint to a new system. It is quite a system I had no ideal there were orphans and uncles in the blockchain though it is good to learn you never know if you might need to use this someday, it is always good to be educated.

  16. after reading the 51% had to come back and read here again and the replies also so very good at helping explain and explain more on the blocks and orphans and then decentralization roughly keeping 51% from happening in the Bitcoin world unlike ethereum classic — just amazes me how much being gone basically for 3 years from crypto world how much and how deep this stuff is ?? great stuff

  17. It is incredible how much I have learned with the reading of these blogs. Yes, I thought that a block was a block from the first one, the genesis block up to the latest block.
    I believed that every 10 minutes a block is added to the blockchain and whatever information less or more than the previous one is chained to wait for the next one.
    I see I had to learn more.

  18. Great Job Sophye! Made a lot of sense but where are the Aunt blocks..lol I love the idea of how they get paid for the various blocks and how some are more than others, which would keep the system honest and more balanced, toward the central goal. I feel so much more interested in this, and will do some research of my own. Thanks Gail!!!

  19. Gail once again blog with a lot of information, and this time got to learn a lot about the new blockchain family and their work. These are amazing blocks, Orphan and Uncle had never heard of them.The blogs of compumatrix have provided us with a lot of valuable information.will read again for info.Thank you Gail for so much information.

  20. learn and learn some more — this is a read that gets better each time i take the impetus and read thru this blog –there is just so much info that is so pertinent to our walk and business and each diff type of block and stale block and how orphans –just so dadgum interesting n great learn !!!

  21. Gail you opened my eyes to a new world today…thank you. I didn’t realize all the various blockchain categories. In the past few months the average citizen is learning more about blockchain with the rumors of voting in the future via blockchain. My mind is wondering how these different categories would come into play if we did vote using the blockchain.

  22. so much appreciation is sent to gail and others here who have helped by posting such great info and just makes it simpler for many I hope to make this online business world much more understandable and simpler to operate — I am reading many of these more than once and it truly helps — thank you sincerely — rjh

  23. i read other blogs on bitcoin and crypto world and then I get led back to this and then I read the Ethereum part of the Uncle and such — and realize just how much there is still to put into perspective and learn beyond Our Crypto Compu Biz and also and then there is this and then — but keep studying n learning piece by piece — much appreciation seriously — rj

  24. Simply put, according to the experts, lot of transactions happen on the blockchain, and maintaining transaction records can help users track what was paid to and by whom. The transactions occurring within a period of time are recorded into a file called block.

  25. When I looked at the graphic in the blog, the thought that came to my mind was wasp nest. The idea in dealing with wasp nest is to examine all protected areas in the vicinity of wasp activity. This is similar to the functions mentioned in the blog as each function relates to the different block types and the functions each serve within blockchain-based protocols.

  26. Many thanks Gail. As always informative and well laid out. Information about Blocks adds to everyone’s knowledge about proof of work Blockchains and their complexity. One thing to remember is that all of the transactions submitted will end up in a valid block, unless someone is attempting a double spend. Might we see an explanation of blocks pertaining to the Delegated Proof of Stake Blockchain, i.e. Bitshares?

  27. Blocks, blocks and more blocks. Fascinating reading. Another epic from Gail. Unfortunately for many of us it is all way above our heads but it is a clear indication that the crypto currency market is simply not fly by night. One can only speculate what it may be like 20,30 and fifty years down the track. Successive generations have much to look forward to.

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