The square knot, known as ma-musubi (ふろしき) in Japanese, is also referred to as the 'reef knot,' and occasionally the 'Hercules knot.' Its diverse names reflect its broad use, including for reefing sails.
Employing a square knot is a prevalent practice when tying furoshiki
used as bags for carrying items. This knot, noted for its stability,
doesn't loosen when applied in such a context. There is a unique, yet
simple technique necessary to untie the knot.
Attention: The term 'square knot' is also associated with entirely different knots, such as the mathematical concept of a square knot, or the friendship knot, which earns its name by being flat, forming a square on one side and a cross on the other.
How to Tie the Square Knot
Cross the left end over the right end and tuck it under, forming a half knot.
Tighten the knot.
Cross the right end over the left end.
Tuck it under, forming a second half knot.
Lightly tie the ends at first to confirm the knot's shape. After adjusting and affirming the shape, tighten the knot, making further adjustments difficult.