In blockchain networks, particularly those that operate using a proof-of-work consensus mechanism, a block reward is the incentive given to miners for their role in validating and confirming transactions. The block reward serves two purposes: it is each miner's reward for their computational work and it is how new coins are introduced into circulation in the network. The value of the block reward can vary depending on the protocol governing the blockchain, and often decreases over time in a process known as 'halving.'