What is Chain Reorganization?

Chain reorganizations, or chain reorgs, occur when blockchain network nodes broadcast two different blocks simultaneously. Since both blocks cannot become finalized, two versions of the blockchain proceed in parallel until one blockchain becomes longer than the other and is chosen to become the sole path forward. In order to ensure that network nodes all agree on the same version of a blockchain, chain reorganization takes place. If a node receives blocks that are part of a new longest chain, then it will essentially abandon the blocks in its old chain in favor of the new ones.