The Fishermans Knot
This is an easy to tie and neat knot that will join cord (and clothes lines!) securely.
The cord from the left passes through the hitch in the cord from the right... and vice versa. Dress the knot tidily and pull tight. It will hold fast, even on slippery ornamental natural or synthetic cord. With this knot the free ends can be trimmed close to the knot after it has been pulled tight without compromising its reliability.
Knot nerds and knit pickers please read on!
When I checked on Wikipedia to see if I had remembered the knot's name correctly I found it had several other names and was formed in the same way as I have illustrated above. So far, so good. But, my original description included the word 'symmetrical'. Close examination reveals that it is not. When I make this knot I use my right hand to make the 'hitch', working with each loose end in turn. This results in two 'right hand' hitches. When the knot is pulled tight it has two sides, the side with two twists visible, four strands, and the side where they are not, two strands.
One of the other names for this knot is 'magic knot'. It is used in knitting. (Knotting yarn for knitting seems to me to be a bad idea. My wife agrees. Change balls at the end of a row. But I need to get back to point.) A video provided shows the production of a truly symmetrical knot with one 'right hand' hitch and one 'left hand' hitch, as in the next image. Is this the result of accident or desgn? I have reproduced it below. The black hitch, on the right, is different from all the other hitches I have illustrated. The 'incoming' body of black cord from the left goes under the white.
This knot pulls tight very neatly with three strands visble on each side. I find this version logically satisfying and worthy of the small extra concentration it takes to produce. Is it as good, better, or less good than the original? Is it technically the same knot, or a recognised variant? Does anyone know or have a serious opinion on this? Please do let me know!