Flat knitting is complicated compared to circular knitting.

Flat knitting is a method for producing knitted fabrics, in which the work is turned periodically, i.e., the fabric is knitted from alternating sides. The two sides of the fabric are usually designated as the right side (the side that faces outwards, towards the viewer and away from the wearer's body) and the wrong side (the side that faces inwards, away from the viewer and towards the wearer's body).

Thus, a knit stitch (as seen from the right side) may be produced by a knit stitch on the right side, or by a purl stitch on the wrong side. This may cause the gauge of the knitting to vary in alternating rows of stockinette fabrics; however, this effect is usually not noticeable, and may be eliminated with practice or by using needles of two different sizes (an unusual way).