There was a block in an old sampler book on my shelf that I skipped for about two years. Not because it looked hard — it was a square with four rectangles around it, five pieces total. What stopped me was the piecing diagram, which had a curved arrow running in a circle and a dashed line partway down one seam. I could not work out what the dashed line wanted, so I turned the page. When I finally sat down and tried it, the whole thing took eleven minutes and I felt a little silly. Partial seams are not a difficult technique. They are an ordering trick, and once you have done one, the diagrams stop being mysterious.
What a partial seam actually is
Nothing about the seam itself is special. You are sewing the same quarter inch, with the same thread and the same foot, at the same stitch length. The only difference is that you stop early — you sew most of the seam, backstitch, and leave the last inch or so open. Then you add the next piece across that open end, and the next, and the next, working your way around. When you come back at the very end and close that first seam, it can finally reach the piece it needs to be sewn to, because that piece now exists.
That is the whole idea. A partial seam is what you use when a patch has to be sewn to a neighbor that has not been attached yet. Sewing it fully on the first pass would trap the corner and leave you nowhere to put the last rectangle without unpicking. Leaving an inch open is the workaround, and it is much older than the diagrams that confused me.
The block that forced me to learn it
The five-piece block I had been avoiding is usually called Bright Hopes, though I have also seen the identical arrangement sold as The Twist. That double naming is normal in traditional patchwork, and it is why quilt historians work from a catalog instead of memory. The standard one is Barbara Brackman's Encyclopedia of Pieced Quilt Patterns, a reference so widely used in quilt history that The Quilters Hall of Fame, which inducted Brackman in 2001, calls it probably the most referenced book in the field. If you are ever unsure whether two blocks with different names are the same block, that is where the answer lives.
Bright Hopes is worth learning on because it is small, it uses scraps, and there is only one partial seam in the whole block.
Cutting and sewing it, step by step
For a block that finishes at six inches, cut one center square at 2½″ and four rectangles at 2½″ × 4½″. That is it. Lay them out on the mat first, rectangles arranged around the center like the blades of a fan, all pointing the same way around, so your eye already knows where each one goes.
- Sew the first rectangle to the right-hand edge of the center square, right sides together. Start at the top, stitch down, and stop about an inch before the bottom raw edge. Backstitch two or three stitches there and cut your thread.
- Press that rectangle away from the center. Every seam in this block presses outward, which matters more than it sounds like it should.
- Turn the unit a quarter turn counterclockwise. The top edge is now the center square plus the end of the rectangle you just added. Sew the second rectangle across that whole edge, raw edge to raw edge, no stopping. Press outward.
- Turn another quarter turn and add the third rectangle the same way, full length. Press outward. Turn again and add the fourth. Press outward.
- You are back where you started, and the last inch of that first seam is still open with the fourth rectangle lying against it. Fold the block so those two raw edges line up, pin, and stitch the gap closed — starting a good half inch back inside your original stitching line and running off the raw edge.
- Press the last seam outward with the rest, then square the block to 6½″ unfinished.
How much to leave unsewn
The open portion has to be longer than the seam allowance of the piece that will eventually cross it, and that is the only real rule. A quarter inch is the technical minimum, which is why an inch is the number I use: it gives me room to get the last piece flat under the needle, and it costs nothing. Leaving too much open is harmless. Leaving too little means the crossing seam sits right at the end of your stitching, and you will be threading a needle through a stiff little wad of fabric to close it.
If you tend to sew past your stopping point on autopilot, stick a pin across the seam line an inch up from the bottom edge. You will feel the needle approach it. I also write PARTIAL on a sticky note and stick it to the machine bed for the first few blocks, because the mistake is never technique, it is forgetting.
Where partial seams beat a set-in seam
Some of these arrangements can be pieced with set-in corners instead, and I would rather not. A set-in seam asks you to stop exactly at a marked point in the middle of the fabric, pivot, and start again — accuracy at a single invisible spot. A partial seam asks you to stop roughly an inch early, which is nobody's idea of precision work, and every other stitching line in the block runs cleanly from raw edge to raw edge. You trade one exact pivot for one approximate stop, and approximate stops are much more forgiving at the end of a long sewing afternoon.
The mistakes that cost me two blocks
Three things go wrong, and all three are recoverable if you catch them early. The first is sewing seam one all the way to the edge out of habit; you will notice when the fourth rectangle has nowhere to go, and the fix is unpicking one inch. The second is pressing a seam toward the center, which builds a ridge exactly where the next seam has to cross, and shows up as a lump in the finished block. The third is closing that final seam without overlapping your original stitches, which leaves a tiny unsewn pinhole at the junction that opens up the first time the quilt is washed. Start the closing seam well inside the old one and that hole cannot happen.
Where else it shows up
Once the ordering trick is in your hands you start seeing it everywhere pieces wrap around something. Any center-square-and-four-rectangles block works this way at any scale, from a two-inch twist to a medallion frame around a big central panel. The technique does not change with the size of the pieces, only the length you leave open.
A short routine for your first partial-seam block
Cut one center square and four rectangles and lay them out around the center before you sew anything, so the rotation direction is decided by your layout rather than by your memory. Put a pin an inch from the end of the first seam and sew to the pin, not to the edge, backstitching there. Press outward, then turn the block a quarter turn and sew the next piece edge to edge. Press outward, turn, sew, press outward, turn, sew. When you are back at the beginning, fold the block, line up the two raw edges of the open gap, and stitch it closed starting a half inch inside your first line of stitching. Press that last seam outward like the others, square the block up, and lay it on the table next to the layout you started from to check that it spins the direction you intended. If it does, cut the pieces for the next four blocks the same afternoon — the technique sticks a lot better if you use it twice in one sitting.