Beginner · Knot guide

Half Square Knot

The Smallest Building Block. The half square knot is exactly what it sounds like — half of a square knot. Stack only the same half and you get a spiral. Alternate halves and you get a flat sennit.

How to tie it

1 Why this knot matters
The half square knot is exactly what it sounds like — half of a square knot. Stack only the same half and you get a spiral. Alternate halves and you get a flat sennit. Take five minutes to practice it on scrap cord before you start any project that uses it — a clean version of this knot will visibly elevate your finished piece, and a sloppy one will pull the whole project down with it.
2 Step 1
Set up four cords: two working, two filler.
3 Step 2
LEFT half: Pass the left working cord over the fillers and under the right working cord. Pass the right working cord under the fillers and up through the left loop. Tighten.
4 Step 3
RIGHT half: Mirror the motion. Right over fillers and under left; left under fillers and up through the right loop. Tighten.
5 Step 4
Stack only LEFT halves: you get a spiral that twists clockwise.
6 Step 5
Stack only RIGHT halves: spiral twists counter-clockwise.
7 Step 6
Alternate left, right, left, right: you get a flat column identical to a sennit of full square knots.
8 Common mistakes
The two most common ways this knot goes wrong: inconsistent tension between knots, and accidentally swapping which cord plays which role. Mark your working cords with a piece of tape until the muscle memory takes over. After a dozen practice repetitions on scrap cord, your hands will know what to do without looking.
9 Where to use it next
Once you have this knot down, every pattern on StitchVault that lists it in its Knots section will feel approachable. Start small — try it in a keychain or coaster project — before scaling up to a wall hanging or curtain. The knot itself is identical at any scale; only the cord length and patience required change.