Antpool Wins One-Block Reorg Over Spiderpool at Height 966,500

On September 11, a brief fork occurred on the Bitcoin blockchain when the two largest mining pools, Antpool and Spiderpool, each mined a valid block that referenced the same parent at height 966,500. The network resolved the split by extending the chain that included Antpool's block, causing Spiderpool's block to be orphaned.

What Happened

Both pools announced blocks at the same height. Galaxy Research, monitoring the network with a private node, observed that its node first saw the Spiderpool block, but the Antpool block later became the longest chain after additional work was added on top of it. The result was a one‑block reorganization, a normal occurrence in Bitcoin's consensus process.

Frequency of One‑Block Reorgs

• This is the third one‑block reorg recorded in the past four weeks.
• Previous incidents occurred at block heights 962,722 on August 16 and 963,853 on August 24.

Context and Significance

One‑block reorganizations are common and typically have minimal impact on network security. They differ from deeper reorganizations seen on other proof‑of‑work networks, such as an 18‑block reorg on Monero and a 100‑block reorg on Bitcoin SV, which can affect transaction finality.

Implications for Users

Transactions included in the discarded block lose their confirmations and must be re‑broadcast. However, the short depth of this reorg means the overall security of the Bitcoin blockchain remains unchanged.