What Is a “Reorg” and How Does It Relate to Block Time and Network Security?

A "reorg" (reorganization) is a temporary event where a blockchain node switches from one chain of blocks to a longer, competing chain. This happens when two miners find a block almost simultaneously, creating a fork.

The chain with the most cumulative Proof-of-Work eventually wins. A high rate of reorgs, often caused by excessively fast block times or low hash rate, indicates network instability and increases the risk of double-spending, reducing security.