Ledger LandISSUE #15 of 90

the genesis block · how chains start

BlockyVSDouble-Spend Dan

Blocky saysThe genesis block is the hardcoded first block — the root every chain grows from.

Block 0, the genesis block, has no previous block, so its hash is fixed in the protocol's code rather than mined/validated normally. It defines the chain's starting state (initial balances, parameters). Bitcoin's genesis famously embedded a newspaper headline. Every node starts from the same genesis, which is part of what defines "this chain" versus another.

Power-ups you unlock

Block 0, hardcoded in the protocol
No previous block to reference
Defines the starting state
Shared genesis defines the chain’s identity

Double-Spend Dan attacks — common mistakes

Thinking genesis is mined like other blocks
Assuming two chains with different genesis are the same
Overlooking that genesis sets initial parameters

Boss battleExplain why the genesis block can’t be validated the normal way.

Example code

<!doctype html><html><head><meta charset="utf-8"></head>
<body style="background:#06040d;color:#e6e0ff;font-family:monospace;padding:20px"><pre>block 0 (genesis): no prevHash → hardcoded
sets initial balances/params
all nodes agree on it = same chain</pre></body></html>

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