The network hashrate is the total computing power all miners worldwide apply to the Nervos network. It is mined with specialised Eaglesong ASICs - an algorithm developed specifically for Nervos, such as the Antminer K7. A rising hashrate means more competition for the same payout - earnings per unit of hashrate decline; a falling hashrate works the other way round. Next to the coin price, the hashrate is therefore the most important network metric for miners; it is also a measure of chain security, since any attack becomes more expensive as total hashrate rises.
CKB stands for Nervos Common Knowledge Base and forms the layer-1 chain of a layered network - a layer-2 tier is additionally planned for scaling. Instead of the classic UTXO model, Nervos uses what is known as the cell model, a generalised form of UTXO. The network hashrate shown here secures this layer-1 base layer.
Nervos has a halving mechanism: the base payout to miners halves roughly every four years. Alongside this there is a secondary emission that runs in addition to the base payout. For miners this means a predictable but gradually declining base compensation, which any investment calculation should factor in. You can model the concrete effect on earnings in the Nervos mining calculator.
Difficulty defines how hard it is to find a valid block, and it continuously adjusts to the network hashrate to keep the block rate stable. Hashrate and difficulty therefore move in lockstep - switch between both metrics in the chart above to see the relationship directly.
Cryptohall24's records go back to Nervos's mainnet launch in November 2019. Since then the dataset grows by one data point per day from our own monitoring - the charts above show the full history with a freely selectable time range.