blockmemento

// block 420000 · 9 July 2016

The second halving

Four years after the first, the second halving came with block 420,000, mined on 9 July 2016. From that block on, a miner earned 12.5 new bitcoins for a block instead of 25, as the rule written into the software in 2009 required. Nobody voted on it and nobody announced it: every node simply refused any block that paid itself more.

The block itself tells of a busier network. It holds 1,257 transactions in 999,838 bytes, a hair under the limit of one megabyte that every block then had to respect. Blocks were full, fees were rising, and the community was deep in the debate on how to make room, which SegWit would settle a year later. Its difficulty, printed on the poster as 213.40 G, had grown more than two hundred billion times since the genesis block, whose difficulty was 1.

Its coinbase, the transaction that pays the miner, carries a personal line: a declaration of love, written by the miner. Miners have always been free to write a few bytes there, and some use them as others use a dedication. The poster prints that line as the chain holds it.

The reward of 12.5 bitcoins lasted until block 630,000, four years later.

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