Great tutorial on the Herringbone Half Double Crochet Stitch via Crochet Nirvana
The herringbone half double crochet stitch may not be the most comfortable for a beginner to learn, but the seasoned crochet fanatic will find it easy to master in no time. This pattern is exceptional for sweaters, cardigans, hats, gloves, throw-pillow covers and you-name-it! The moves might seem a bit awkward at first, but once you get the pattern down, you can almost do this stitch without thought. The results are phenomenal and you can make so many neat birthday or holiday items for you and the family. Get your crochet hook and yarn ready to follow these easy steps:
1) Begin a simple chain stitch. You need to have 2 available loops to start the herringbone half double stitch.
2) Put the yarn over and insert the hook into the next stitch.
3) Put the yarn over again and pull it through that stitch until it forms a third loop on the hook.
4) Pull the first loop through the second loop.
5) Put the yarn over and pull through both loops.
6) Repeat this process until you have completed a row. Each additional row will change the direction of the design and give it the distinctive herringbone effect.