The name «Grief knot» comes from a combination of ‘granny’ and ‘thief’, because the Grief knot combines the features of the latter two knots. It is the trickiest of the three Reef knot twins, very insecure. However, it can be used as an element of other knots, such as the Carrick bend.
ABoK #1208, #1406, #1407, #1459, #1490, #2579
Fold the rope to form a loop with the running end downside.
Thread the 2nd running end through the loop from beneath.
Pass the 2nd running end under the 1st one and then over the 1st standing part.
Pass under the 1st standing part and through the loop.
Tighten the knot.
The Grief knot is complete.