Shard Chain

A shard chain is a separate chain within a sharded blockchain, running in parallel with others and handling its own share of transactions and data, while a central chain coordinates them. The term is most associated with Ethereum's original long-term roadmap, under which the Beacon Chain would coordinate 64 shard chains to raise capacity. From around 2020 Ethereum's developers changed course: rollups would handle execution, and the main chain would instead provide cheap data space for them, an approach that led to the "blobs" introduced by the Dencun upgrade in 2024 and to a design called danksharding. Shard chains as first imagined were therefore never launched on Ethereum. Other networks use related designs, with shards or parallel chains secured by a common validator set, as with the parachains of Polkadot's relay chain. Also see sharding.