My friend Nettie recently introduced me to what she calls the Abrupt Increase, AbInc, stitch. Apparently, this stitch has an official name: the foundation stitch. This is an advanced technique that can be used deliberately or to correct mistakes. It essentially creates a new chain under each stitch, allowing you to work more free form. Nettie explains the stitch, and shows a purse she made using the stitch along with the pattern.
Have you ever made your chain and worked the first row of your project only to discover that you miscounted your chain? Instead of pulling it all out and starting over you can simply do the foundation stitch to add another chain. This is particularly useful because counting the chain and working the first row are the most tedious and attention requiring parts of crocheting.
Another use for the foundation stitch is to abruptly increase the number of stitches per row. That is the what Nettie did in making the clutch. She used it to make the sides of the purse.
My favorite use for the stitch is its application to Tunisian crochet. Before I learned this stitch, I would chain the length of the row, then I would chain the height of the row, and then finally I could begin. The problem with that is that my chain is rarely perfectly even and consistent with the space my actual stitch takes up. The old method is pictured. Notice the chain on the left side of the work. With the new method, you simply chain the height and work your stitch until you are content, the starter chain is unnecessary. Less planning is needed and the side with the starting chain is not too loose or too tight because there is no starting chain.