What is a DAA score and why does it control Kaspa's emission phases?

In Kaspa, the DAA score is the network-level milestone that determines when one emission phase ends and the next begins. Rather than using a fixed date, the protocol defines a target DAA score for each phase transition; the network moves to the next phase only after that score is reached. Because the DAA score rises with every block added to the DAG, and because block production speed depends on how much total hashrate miners are contributing, the real-world timing of each transition shifts whenever mining activity changes significantly. Understanding this matters because it explains why two different estimates of the same phase date can both be correct — they were simply calculated under different assumptions about future hashrate.