Child Block

Overview

The parent-child link creates blockchain order. A child header normally contains the hash or identifier of its direct Block Parent. Nodes use this reference to find the state and consensus context needed to validate the child. The child’s block number, timestamp, resource accounting, and state transition are checked relative to the parent under the active protocol rules.

Multiple producers can create valid children for the same parent. This can happen through normal network latency, competing proposals, or an intentional fork. The children begin separate branches, and each later child extends one of those branches. Best Chain selection evaluates the accumulated work, votes, checkpoints, or other protocol weight to decide which path becomes the best and canonical chain.

The term is narrower than descendant block. A grandchild or later block descends from an earlier block but is not its direct child. Confirmation depth is often counted by the number of canonical descendants above a block. A child adds one level of depth, but it may be replaced if another branch wins. Stronger finality depends on the network’s consensus mechanism, not the family-tree label alone.

Payment systems can use child links to validate ancestry and detect reorganizations. If a new canonical child references a different parent than expected, the local chain view may have changed or data may be missing. Records should maintain block IDs and parent IDs for processed events. This allows software to reverse provisional state and replay the correct branch instead of relying only on increasing block numbers.

The relationship is evaluated against the exact parent hash, consensus rules, and resulting state transition rather than the child’s height alone.