Bitcoin Network Experiences Rare Two-Block Reorg, What Does It Mean?

The Bitcoin blockchain recently experienced a “rare-ish” two-block reorganization (reorg). 

The term “reorganization” can sometimes sound alarming to casual observers, but the event was not an attack or a glitch. Bitcoin’s decentralized consensus mechanism is functioning exactly as designed. 

According to data shared by Bitcoin researcher b10c and visualized on-chain, the mining pool Foundry USA won an epic multi-block race against competitors AntPool and ViaBTC.

The race at height 941880

In order to validate the next block of transactions, miners are constantly competing to solve complex cryptographic puzzles 

The he network briefly split into two competing chains at height 941880. AntPool successfully mined block 941881. Shortly after, on that same path, ViaBTC mined block 941882. Simultaneously, Foundry USA mined its own version of block 941881. Foundry then found the next block as well, creating its own version of block 941882.

At this point, the network had two valid chains of equal length. The tie was finally broken when Foundry USA continued its winning streak with blocks 941883, 941884, and 941885. 

The blocks mined by AntPool and ViaBTC were discarded, becoming what are known as “stale” or “orphaned” blocks. In total, Foundry USA pulled off seven consecutive blocks (from 941879 to 941885).

Single-block reorgs happen periodically. However, a two-block reorg is much rarer. It means that the temporary tie between the two chains persisted for an entire extra block cycle.