YO on the first stitch?

I am doing this pattern: http://www.ravelry.com/patterns/library/my-heaven

Casting on is not a problem, but the very first instructions are:

Lace Edging. Cast on 23 sts.
Row 1 (RS) – yo, k2tog, knit to end of row.
Row 2 (WS) – knit.
Repeat the last two rows once more.

Now I think you just put the working yarn on your right needle and then K2tog (the first two stitches) off the left needle.

Why do it this way? Don’t you still just end up with 23 stitches on the needle? I don’t under stand the purpose of the K2tog in these instruction. I have checked for errata and nothing pertains to these instructions. I don’t see how this puts a hole at the beginning. It would make my brain feel better if I knew why and maybe how the YO is the first stitch. Thank you for your wisdom!!!

Yes, the yarn over is made by laying the yarn across the right needle from front to back. The k2tog keeps the stitch count unchanged. The reason for the yo is to give you a small loop at the edge. After you finish the edging shown on charts A and B you’ll pick up stitches for the main body of the shawl in the loops, 4 loops from each repeat of chart A and 6 from chart B repeats plus a few more.
"Triangle section. With circular needle and RS of Edging facing, pick up and knit 1 stitch into each yarn over 138 {168} times."
Give it a try on a small garter stitch swatch and you’ll see the loop.
Spectacular shawl pattern! Enjoy knitting it.

Thank you so much. Now that you say that it makes sense. Thank you for taking the time to answer me.