Quick fix: Thread a length of matching yarn onto a tapestry needle and use it to close the hole from the wrong side with small, tight stitches in a figure-eight pattern around the gap. Block after to help the repair blend in.
What you are seeing
A hole at the corner where the sleeve stitches join the body in a seamless sweater — usually a top-down raglan or yoke construction. The hole may be 1–3 stitches wide and sits right at the underarm, which is a high-stress area.
Why it happens
- When sleeve stitches are placed on hold and body continues, the join point is loose and vulnerable
- The underarm cast-on creates a gap that isn't fully closed during assembly
- Picking up too few stitches at the underarm during sleeve construction
Fix it now
- Turn the sweater inside out and identify the hole at the underarm corner.
- Thread a tapestry needle with a 30 cm length of matching yarn.
- Weave the yarn around the edges of the hole in a figure-eight pattern, drawing the edges together snugly without puckering the fabric.
- Weave in both tails securely on the wrong side.
- From the right side, use the tips of your fingers or a blunt needle to gently redistribute the yarn around the repair so it blends in.
- Block the underarm area: mist with water, gently stretch and pat flat, then let dry.
Prevent it next time
- When picking up stitches at the underarm, pick up one extra stitch at each corner of the cast-on edge — these corner stitches close the gap before it can form.
- On the first round after picking up underarm stitches, k2tog at each corner to eliminate any gap stitch.