invisible decrease (dec)

To do a invisible decrease stitch. The decrease means combining 2 stitches into 1 stitch.
  We just insert the front loop only in the next stitch, we don't do a yarn over but continue to insert the front loop only in the next stitch.
   Now we have 3 loops on the hook, we do a yarn over and through the first 2 loops. There are 2 loops left on the hook. Do a yarn over and through these 2 loops. The decrease stitch finish.
  Do it again…… It's called decrease.

Video

We just insert the hook into the front loop only in the next stitch.

We continue to insert the hook into the front loop of the next stitch.

Now we have 3 loops on the hook, we do a yarn over and through the first 2 loops.

There are 2 loops left on the hook.

Do a yarn over and through these 2 loops.

There 1 loop left on the hook. An invisible decrease stitch finish.