At 1:28am GMT block 620,537 was mined and Bitcoin SV nodes of v1.0.0 or greater began accepting transactions under the restored Genesis protocol.  At 1:55am at block height 620,539 the first block containing a Genesis-only transaction was mined, locking in the change. Old node software did not accept this block and forked off onto a legacy chain as intended.

The transaction that triggered the chains to hard fork was https://whatsonchain.com/tx/4ec3b63d764558303eda720e8e51f69bbcfe81376075657313fb587306f8a9b0

This transaction was prepared in advance by the Bitcoin SV team and broadcast as soon as block 620,537 was mined. The transaction violated the old limitation for arithmetic inputs of 32 bits and was deemed invalid by old nodes whilst being valid under the Genesis rules which mirror those of the original protocol implemented by Satoshi Nakamoto. It contained the following 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.”

The transaction did not get mined into block 620,538 which was mined by an unknown miner, hence old nodes continued to follow the majority chain for one block longer than expected. There may have been other transactions with similar properties in the same block (620,539) however as this transaction was prepared specifically for the purpose of forcing legacy software to fork off we are referring to it as the “lock-in transaction”.

What is also notable about this transaction is that the above message was embedded twice. Once in the well known form of an OP_RETURN output but also embedded in a spendable output using Satoshi’s original pay-to-public-key script template.  We believe this may be the first ever transaction that embeds data in a spendable output using this technique.  To preserve this piece of history, the private key for this output has been destroyed and as such it will remain a permanent part of the UTXO set for as long as ECDSA remains secure.

The forking block (620,539) was mined by Taal.com and contained the coinbase string: “taal.com on behalf of Satoshi Nakamoto” which the Bitcoin SV node team feels is a fitting tribute to the proof of work displayed by Satoshi in creating the Bitcoin protocol and the efforts of miners to restore to his original design.

The legacy chain has been extended by an unknown miner by one block since the fork.  This is most likely due to a small miner not upgrading their node to v1.0.0 or greater before the fork.  We will continue to monitor the state of both chains however at the time of writing the Genesis chain is 75 blocks ahead of the legacy chain and widely supported across the ecosystem.

We note reports of up to 100 nodes remaining on older versions of the software.  The Bitcoin SV team does not regard this as problematic as there is no evidence of a significant amount of hashing power backing this legacy chain and it is expected to cease being extended. Older versions of node software that are not mining are not contributing anything useful to the network and their removal is beneficial to the Bitcoin network by making propagation amongst upgraded nodes more efficient.

This is, without question, the largest set of consensus changes ever attempted in the history of Bitcoin and no change of such magnitude is done without some level of risk.  However, given that the Genesis hard fork of Bitcoin is now 75 blocks ahead of the legacy chain and in the absence of any notable problems, the Bitcoin SV team considers the Genesis upgrade to have been successfully activated.

We would like to thank all of the miners that participated in the upgrade and offered assistance in various ways. 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.

Now that full capabilities of Bitcoin script have been unlocked we look forward very much to seeing what application developers will begin to do with that capability.  This is the beginning of Bitcoin becoming what it was always meant to be.

Lastly we would like to offer our heartfelt thanks to Mr Calvin Ayre who made the formation of the Bitcoin SV team possible in 2018 and whose ongoing support has enabled it to grow to become the largest and most highly skilled engineering team in the history of Bitcoin.  Without Calvin Ayre’s support Bitcoin would have died 14 months ago but because of his support it has been now restored to the state that Satoshi Nakamoto intended.

Thankyou.

On behalf of the entire Bitcoin SV team,

Steve Shadders and Daniel Connolly