Fresh liquidity and persistent liquidity

This is the distinction that separates a beginner from an order flow reader. Not all orders in the book carry the same weight, and the difference cannot be seen on the book: it shows up over time, which means on the heatmap.

Fresh liquidity

Orders that have just appeared. They signal a new intention, but they are also the most likely to be cancelled or moved if price takes its time. A sudden appearance as price approaches can be a reactive or defensive order, or a decoy: be suspicious.