A slipped half hitch is a half hitch that has been tied with a bight rather than the end of the rope. The advantage of the slipped half hitch is that it can be untied by pulling on the end of the rope, which makes it easier to undo a jammed knot.
A slipped half hitch can be tied anywhere you are worried about jamming.
It can be tied on its own, but it’s most commonly used to “slip” a larger knot like two half hitches.
1Go under and around the pole.
2Go under the standing part.
3Make a bight in the working end and pass it back over the standing part and under the working end.
4Snug the knot.
This knot is ABOK # 394
A knot that incorporates a slipped half hitch is said to be “slipped”.