Here’s the transaction that locked in Genesis

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The Bitcoin SV Node team has published a more detailed explanation of the February 4 hard fork that activated Bitcoin v1.0.0, or “Genesis”. Team leaders Steve Shadders and Daniel Connolly said they considered the upgrade successful, its changes locked in irrevocably.

We noted that the first Genesis block was actually mined by an unknown miner. It’s still not known who that miner was, and it seems to have happened more by coincidence than design. The block that “locked in” Genesis was actually the second block, #620539.

How does that work? Well, even though Genesis rules applied as of block #620538, the unknown miner’s block didn’t actually contain any transactions not allowed under the previous “Quasar” rules. So while Genesis was technically activated, non-consensus nodes (those still running the older software) remained on the network. To hard-fork the chain, a block must contain transactions not allowed. This would bump any non-consensus nodes from the network since only consensus nodes could extend the chain.

Once the consensus chain has extended past the non-consensus chain for a certain time (more likely if it has far greater hashing power) the hard fork changes can be considered a success. At press time, the consensus chain is over 120 blocks long.

The Bitcoin SV Node team prepared a more complex transaction specifically for the purpose—which is common practice after upgrades of this type, either by the development team or third parties looking to support the changes. Similar transactions occurred in the wake of the August 2017 BCH hard fork, where users sent non-Segwit transactions over 1MB in size that would be rejected by BTC’s chain.

The team’s transaction contained the message: “On February 4th, 2020 The Return to Genesis was activated to restore the Satoshi Vision for Bitcoin. It is locked in irrevocably by this transaction. Bitcoin can finally be Bitcoin again and the miners can continue to write the Chronicle of everything. Thank you and goodnight from team SV.”

A historic moment in block 620539 that confirmed new #Genesis rules as valid on #BitcoinSV #BSV. Block mined by @TaalBlockchain and message delivered by @shadders for @BitcoinSVNode team.

It's a good night from Team SV . . . and a new dawn for Bitcoin. ☀️ pic.twitter.com/UUbPy12KTX

— Jimmy Nguyen (@iamJimmyWIN) February 4, 2020

They embedded that message twice: once in an OP_RETURN output, but also in a spendable output using Satoshi’s original pay-to-public-key script template. The transaction contained arithmetic inputs of over 32 bits, which was not allowed under the previous rules. This was rejected by nodes running older software, forking them off the main chain.

Some nodes still running the old software

Shadders and Connolly noted they’d heard reports of up to 100 nodes still running the old software. At the time they published their announcement (at around 75 Genesis blocks) an unknown miner had extended the legacy chain by just one block.

Whether that’s a result of neglect or otherwise isn’t certain, but it’s not a problem for BSV. Several of those nodes may have upgrades a day late, others would have left the network—and any still mining the other chain today are simply wasting electricity.

They also thanked Calvin Ayre for his support in keeping Satoshi Nakamoto’s original vision for Bitcoin alive, and all the miners who supported both the fork and network in general.

The governance of Bitcoin consensus parameters is now in your hands.  We will be available to advise but we will resist making recommendations and will no longer be making any decisions on your behalf. We know you will take this significant responsibility seriously perhaps because you care about Bitcoin but most certainly because it’s in your economic interest to do so.