Chapter 64 classifies footwear on two materials and only two: the upper and the outer sole. A running shoe, a dress shoe and a safety boot share a heading whenever those two materials coincide.
This is the chapter where commercial intuition misleads most. Neither purpose, nor price, nor brand enters the classification. Note 4 sets out how to determine the constituent material where several are present: it is the one with the greatest external surface area.
Every number opens on the lines beneath it, down to the eight-digit statistical code.