Blockchain Semantics Insights

Business Case |  Deep Tech |  Announcements |  Blockchain Glossary | 
Blockchain Semantics Blog What is a Genesis Block?

What is a Genesis Block?

By Abhishek Singh | April 6, 2018, 7:59 a.m. GMT

The Genesis Block is also known as Block Zero or Block 0. It is the ancestor that every Blockchain network’s block can trace its origin back to. Remember how every block in a Blockchain is linked back to the previous block using a hash in the block header? You keep going back and you realize every block is hence linked to the genesis block. 

It is literally the first block in the Blockchain. It is probably the founders (like Satoshi Nakamoto for Bitcoin) or (Vitalik Buterin for Ethereum) who must have mine the genesis block themselves. No competition amongst miners or for that matter even miners exist when the genesis block is being mined!

In simpler words, a genesis block is the first block of the Blockchain. It defines initial parameters of the Blockchain like level of difficulty, consensus algorithm etc. to mine blocks. It is the only block in the Blockchain that doesn’t refer to previous block because there isn’t any. It may not even hold any transactions if no tokens are pre-mined before the genesis block. Of course, different Blockchains may differ somewhat on some of these postulates. 

The genesis block differs slightly in the way it is created from a normal block. It is hard-coded into the Blockchain network’s clients for the main network. For the other blocks of course all the clients play a role or participate in the creation of.

Significance of Genesis Block

Two nodes will both connect to the network only if they have the exact same genesis block. It implies that block synchronization will only happen if peers have the same genesis block.

You are probably wondering about the contents of a genesis block. Here is what the genesis block of the Ethereum Blockchain holds.





1438269973(Jul-30-2015 03:26:13 PM +UTC)


8893 transactions and 0 contract internal transactions in this block



Parent Hash




Mined By

0x0000000000000000000000000000000000000000 in 15 secs



Gas Used


Gas Limit




Block Reward

5 Ether

Uncles Reward

0 Ether

Extra Data



One last thing to remember about genesis blocks. The fact that a Blockchain has its genesis block created does not necessarily imply that it is off to a great start. There is still typically a lot of work yet to be done around creating a community, getting miners on-board, getting peers to transact and then subsequently other blocks get created. It is believed that after mining the genesis block for the Bitcoin Blockchain the next block, known as Block 1, took almost six days to come about. Of course, now all of us know that the average duration between two blocks is closer to 10 minutes. Multiple interpretations exist for this delay of six days. Some believe that Nakamoto spent six days mining the original block as a test of the system in order to ensure its viability and then backdated the timestamp. More colorful and spiritually oriented followers believe he intended to recreate the story of God's rest after creating the world in six days. Not a lot of this needs to make sense to you, save for one fact- the genesis block is the very first block of a Blockchain and all blocks ever created are eventually back-linked to it. Bingo!





If you liked the post, give it a   0
Apply for Blockchain Jobs

Course 1

Introduction to
Blockchain and Bitcoin

Course 2

Developing Decentralized
Applications on Ethereum
Using Solidity

Course 3

Investing In Bitcoin
and Cryptocurrencies


Be the first to comment.