The alternative genesis block — Satoshi's pre-release test block from September 2008

On October 6, 2022, security researcher SerHack published “The Story Behind the Alternative Genesis Block of Bitcoin,” analyzing a pre-release version of Bitcoin’s genesis block that predated the official launch by nearly four months.

Discovery: On December 23, 2013, BitcoinTalk user “Cryddit” (Ray Dillinger, aka Bear) posted source code that Satoshi Nakamoto had shared with him privately in November 2008 for a security audit. Dillinger reviewed the blockchain code while Hal Finney reviewed the scripting language. The code contained a genesis block with entirely different parameters from the one that launched on January 3, 2009.

The Pre-Release Genesis Block:

ParameterPre-Release (Sept 2008)Official (Jan 2009)
Timestamp1221069728 (Sept 10, 2008 18:02:08 UTC)1231006505 (Jan 3, 2009 18:15:05 UTC)
Hash0x000006b15d1327d67e...0x000000000019d6689c...
Difficulty (nBits)20 (“ridiculously easy”)0x1d00ffff (Difficulty 1)
Nonce141,7552,083,236,893
Block Reward10,000 units (“cents”)50 BTC

Connection to the Financial Crisis: The pre-release genesis block’s timestamp of September 10, 2008, coincides with the day Lehman Brothers announced approximately $3.9 billion in quarterly losses. Lehman Brothers filed for bankruptcy five days later on September 15, 2008. This suggests Satoshi was developing Bitcoin with the unfolding financial crisis as direct motivation — even before the whitepaper’s publication on October 31, 2008.

Other Pre-Release Differences: The November 2008 code also contained an early IRC client framework, a peer-to-peer marketplace, and a virtual poker game — features that were removed before the January 2009 public release. The total supply under the pre-release parameters (10,000 units per block) would have been approximately 1.99 billion bitcoin.