The Neckline Test

It's fairly easy to test if your garment neckline is kosher or not.  We use the "necklace test" as recommended by Rabbi Eliyahu Falk, in his book, "Modesty - An Adorment for Life."  If your garment neckline is outside the vertical part of the perimeter (circumference) of the necklace, then the neckline is not kosher.  If your neckline shows your collarbone, then it is also not kosher.

Here is a picture I took that demonstrates this effect.

See there are two shirts being worn on the dress form.  The white shirt's neckline is beyond the vertical line of the perimeter of the necklace (in silver cord), hence it is not kosher.  The taupe shell worn underneath the white garment has a neckline that sits right inside the perimeter of the necklace and is deemed kosher. There is no way to check for the collarbone here as this is only a dress form, but the collarbone normally sits about one inch below the horizontal part of the neck, and it varies from woman to woman.

I hope this article helps someone! Happy sewing!