Closed herringbone stitch has an almost solid line along it's upper and lower edges. This is formed by working an additional stitch through the same pleats. It is much firmer than open herringbone stitch.

1.  Secure the thread on the back of the fabric. Bring it to the front on the upper pleating row, through the left hand side of the first pleat.

2.  Keeping the thread above the needle, take it from right to left through the pleats 2 and 1 on the upper pleating row.

3. Pull the thread through.

4. Still keeping thread above the needle, take it from right to left through the pleats 3 and 2 on the lower pleating row.

5. Pull the thread through.

6. Keeping the thread below the needle, again take it from right to left through pleats 3 and 2 on the lower pleating row.

7. Pull the thread through. Still keeping the thread below the needle, take it from right to left through pleats 4 and 3 on the upper pleating row.

8. Pull the thread through. With the thread above the needle, again take the needle from right to left through pleats 4 and 3 on the upper pleating row.

9. Pull the thread through. Continue to end the row. For the last stitch, take the needle to the back through the right hand side of the last pleat.

10. Pull the thread through and end off. Completed closed herringbone stitch.