At a forge hearth, glowing billets cool through shifting hues. Tap exactly when the critical quench color appears—early cracks the piece, late softens it to scrap. Later stages run several billets together with furnace flicker that muddies the read. Perfect and good windows score apart, perfect chains add combo points, clear every billet to finish, and end the stage after three scraps.
Watch cooling steel and tap at the critical quench color.