Genesis Block

The genesis block is block 0 of the Bitcoin chain - the first one. Satoshi Nakamoto mined it on January 3, 2009, and embedded a now-famous message in its coinbase transaction:

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

This was a verbatim Times of London front-page headline from earlier that day. It serves two purposes. First, it proves the block wasn't pre-mined - it couldn't have existed before the newspaper headline did. Second, it's an unmistakable statement of intent: Bitcoin launched in the middle of a banking crisis, explicitly invoking the failures of the system it was designed to compete with.

A few technical quirks of the genesis block:

• The 50 BTC block subsidy is unspendable. Satoshi hard-coded it in a way that's not part of the UTXO set. The coins exist in lore but not in the spendable supply.
• No previous block hash. The previous-block-hash field is all zeros, since there's nothing before it.
• Hardcoded into Bitcoin Core. Every node ships with the exact bytes of the genesis block baked in. It's not "found" by the network; it's a constant.

The genesis block is mostly symbolic now, but the message is worth re-reading on every halving. It's the founding document of an alternative monetary system, written in 80 bytes by someone who hasn't been seen since.

See the whitepaper for the companion document, and Satoshi Nakamoto for what we know about who put it there.