A pour-over framework that gives independent knobs for the two things a pour schedule can still control: the cup’s balance and its strength (see Most Cup Character Is Fixed Before Brewing). The total hot water splits into a 40% stage and a 60% stage: with 300g of water, 120g then 180g, each stage further divided into individual pours. The first 40%, hitting mostly fresh grounds, sets the sweet/acid balance, tuned by shifting water between its pours; the remaining 60% sets concentration, tuned by how many pours it is divided into. In Coffee Brewing Control Chart terms, the first knob steers extraction character (because Coffee Compounds Extract in Order) and the second steers strength.
The mapping holds only because the method fixes the variables that would entangle it: coarse grind, fixed water temperature, letting each pour drain fully. The knobs still touch at the edges (total water is fixed, so extra second-stage pours raise strength partly by raising extraction), but they are separate enough for one-variable debugging: too sour, shift water toward the first pour; too weak, add a pour to the second stage.
Devised by Tetsu Kasuya, who used it to win the 2016 World Brewers Cup; his blog at Philocoffea walks through the full recipe.