What is block window sparsity in Kaspa?

Block window sparsity is a sampling parameter that controls which blocks Kaspa considers when calculating mining difficulty. It is defined as sparsity = length × BPS ÷ size, meaning the algorithm uses roughly one out of every 'sparsity' blocks rather than every block. Sparsity is the only parameter affected by BPS (blocks per second), and setting it to 1 recovers the original non-sparse behavior where every block is included. For beginners, this matters because it allows Kaspa's difficulty adjustment to stay accurate and consistent even as the number of blocks produced per second changes — keeping mining fair across varying network conditions.