"Between your eyes" — read as the hairline

The verse says bein einecha, between your eyes. The head-box is not worn between the eyes. It is worn on the top of the head, forward, so that its lower edge sits at the hairline, centred; the knot goes at the nape, and the two strap-ends hang forward over the chest.

The reading is exegetical and old: between your eyes is taken to mean on the line that is between your eyes, extended upward — the vertical midline of the face, continued to where the hair begins. The Talmud derives the height from a comparison with another commandment about the head.

Which is worth noticing as a piece of interpretive method, because it is the opposite of literalism and the opposite of allegory. Nobody says the phrase is a metaphor. They take it with complete seriousness as a location, and then argue about geometry. The verse is treated as a specification with an ambiguity in it, and the ambiguity is resolved the way you would resolve one in a drawing.

Practically: it must sit on scalp rather than hair-covering, above the point where the hair starts, and it must be centred — three requirements that between them make a box worn low on the forehead, as it is usually drawn by people who have never worn one, incorrect on every count.