*Warning: serious rope geekery ahead. You have been warned.
The reef knot (also known as a square knot) is an ancient, well-understood knot, which takes its name from it’s utility in “reefing” sails to reduce their surface area during periods of high wind while also being easy to untie when wet. The reef knot was particularly desirable for this purpose because of its strength under moderate load, coupled with the ease with which is can be collapsed (spilled) by pulling one of the free ends.
In the context of its use as a single-column tie at the start of a gote (or takate kote) one interesting property of the reef knot is that only one of its ends is collapsable. When tied one way (starting by going over the wrists in a ‘hands behind the back’ bondage context) then it is the working end that collapses the knot, which is of course undesirable. However, when tied another way (starting by going under the wrists) it is the bight end of the rope that collapses the knot, which may be a useful feature for fast untying. Note that the reef knot only functions properly when tightened/compacted.
Most knots/frictions/bends we use in rope bondage have names and a long history outside of the bondage world, as such many of their properties have already been studied and revealed.
For example, when we tie our shoelaces, we are tying a single-column tie, and here you can find a link to an in-depth study on this published in the respected journal Nature: What is the best way to lace your shoes? pdf (only the last paragraph is really interesting here).[youtube.com/watch?v=iKAN9q-_r3k]