There are many types of bobbles created using different techniques. The basic concept for all bobbles - regardless of their size - is that you are taking one stitch and increasing it multiple times, knitting on those stitches only for a few extra rows, then decreasing them back down to one.
This particular bobble is the one used in our Year of Mittens September Mitten. For this bobble, yarn overs increase 1 stitch into 5, then decreases reduce the count down to three, then back down to 1. The combination of additional width (created by increasing stitches) and length (created by just working back and forth on the bobble stitches) makes the bobble…well…bobble-y!
Note: For many of the images, the stitches have been stretched out slightly to show as much individual stitch detail as possible. It is not necessary to stretch your knitting in the same manner as you work the bobble.
STEP 1a /
When you get to the bobble symbol in your chart,
increase into the first stitch on the left hand needle by working a (k1, yo, k1, yo, k1) into the stitch - 1 stitch increased into 5. As you can see in the photo above, there are 5 new stitches tightly packed next to one another on the right hand needle. These form the start of the bobble.
STEP 1b /
Turn the work so that the wrong side is facing. The 5 newly increased stitches are on the left hand needle, and the working yarn is at the right.
STEP 2a /
Purl the 5 newly increased bobble stitches. One row of length has been added to the bobble.
Step 2b /
Turn the work around again so the right side is facing. The 5 stitches of the bobble are on the left hand needle and the working yarn is at the right.
STEP 3a /
Decrease by working a (k2tog, k1, k2tog) over the next 5 stitches. This adds another row of length, and decreases the bobble from 5 stitches down to 3.
STEP 3b /
Turn the work so that the wrong side is facing. The 3 stitches of the bobble are on the left hand needle, and the working yarn is at the right.
STEP 4a /
Work a p3tog to decrease the remaining three sts together down to one stitch. Another row of length has been added, and the bobble has been decreases from 3 stitches down to 1.
STEP 4b /
Turn the work around one last time, then slip the st back to the right hand needle. The stitches and yarn are now in position to continue working around in the pattern as charted.