How to Crochet A Foundation Chain
Almost all crochet begins with a foundation chain, which is a series of chain stitches beginning with a slip knot. You then work the first row of other stitches into the chain to start making crochet fabric. The foundation chain is also called a base chain or starting chain.
To work a foundation chain, start by making a slip knot.
Then chain as many stitches as the pattern calls for.
When working into the starting chain, you may work under one or two strands of chain loops as shown in the illustration. Either of these methods forms an even, firm bottom edge.
Some people like to work into the "bump" on the back of the chain. This forms an even, stretchy bottom edge that is ideal for garments. It also produces an edge that looks more similar to the final edge of your project, making it useful for projects where both ends are exposed, such as scarves.
Whichever method of working into the foundation you choose, be consistent. Work all the pieces of a project in the same manner.