What Happens When Two Miners Find a Block in the Same Second? How the 'Orphan Race' Unfolds
Bitcoin mining is a race without a real-time referee. A newly mined block must physically propagate across the global peer-to-peer network before consensus is reached on the chain's tip. This takes seconds, sometimes longer on congested connections.
If a second miner finds a valid block before learning of a competing one, they build on their last-known version and broadcast their own block. For a short time, two equally valid blocks exist at the same height, creating a temporary chain split. The network resolves this not by voting or timestamps, but by Proof-of-Work: the chain that accumulates the most work becomes canonical. Blocks on the losing side are "orphaned" or "stale." Their miners lose the block reward and fees, though unconfirmed transactions return to the mempool. Usually, a single subsequent block resolves the tie.
A notable two-block reorganization occurred on March 24, 2026. Antpool and Foundry USA mined competing versions of block 941,881 seconds apart. ViaBTC extended Antpool's chain, while Foundry extended its own, creating a one-block split. Foundry then pulled ahead by mining six consecutive blocks, making its chain the heaviest. All nodes switched to Foundry's chain, orphaning blocks from Antpool and ViaBTC.
While such multi-block reorganizations are rare, the underlying race condition is common. Analysis shows about 9.2% of block intervals in a sample period were under 60 seconds, each representing a potential short-lived race. Fast relay networks have reduced propagation delays, making prolonged splits rarer. However, the event highlighted a trend of hash rate concentration, where well-resourced pools have a higher chance of winning any specific race and mining consecutive blocks, marginalizing smaller miners.
cryptonews.ruYesterday 08:36
