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Genesis Block

The Genesis Block is block height 0: the first block in the Bitcoin blockchain and the moment the network went live. It was mined by Satoshi Nakamoto on January 3, 2009, with a block reward of 50 BTC.

The Coinbase Message

The block’s coinbase transaction embeds a short text in its input data, arbitrary data miners are free to include. Satoshi chose a headline from that day’s The Times (London):

"The Times 03/Jan/2009 Chancellor on brink of second bailout for banks"

That line does two things: it timestamped the block (proof it wasn’t pre-mined before that date) and stated Bitcoin’s purpose: an alternative to a financial system dependent on central bank bailouts. The headline referred to the UK Chancellor of the Exchequer and bank rescues during the 2008–2009 crisis, the same context in which the Bitcoin whitepaper had been published weeks earlier.

In the raw block data, the message appears as readable text in the coinbase input. The hex dump below shows the block bytes; the right-hand column is the ASCII interpretation, where the headline is visible.

Genesis block hex dump showing The Times headline in the coinbase data

Genesis block data: the coinbase message visible in the hex dump (right column)

Technical Details

  • Hardcoded: The genesis block is hardcoded into Bitcoin clients as the fixed root of the chain. Nodes accept it by definition rather than by verifying a previous block.
  • Block hash: The mainnet genesis block hash is 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f. You can view the block on a block explorer.
  • Unspendable reward: The 50 BTC created in the genesis block cannot be spent. Due to a quirk in the original implementation, that output is not considered spendable by the consensus rules, so those coins are permanently locked. Block 1 (mined days later) is the first block whose reward could eventually be spent.

See Also