Bias knitting is a method by which the grain of a knitted fabric

Knitted fabric

Knitted fabrics is the third major class of fabric, after woven and nonwoven fabrics.-Elasticity, thickness and warmth:Compared to the other two classes, knitted fabrics are much more elastic, which accounts for their historical use in stockings and other clothing that requires changes in shape...

 is skewed from the vertical, by decreasing on one side and increasing on the other. The term "bias" derives from sewing

Sewing

Sewing is the craft of fastening or attaching objects using stitches made with a needle and thread. Sewing is one of the oldest of the textile arts, arising in the Paleolithic era...

, where bias refers to the diagonal between the weft and warp threads, where the elasticity of woven

Woven

A woven is a cloth formed by weaving. It only stretches in the bias directions , unless the threads are elastic. Woven cloth usually frays at the edges, unless measures are taken to counter this, such as the use of pinking shears or hemming.Woven fabrics are worked on a loom and made of many...

s is greatest.

A classic use of bias knitting is in making a saw-toothed knitted hemline

Hemline

The hemline is the line formed by the lower edge of a garment, such as a skirt, dress or coat, measured from the floor.The hemline is perhaps the most variable style line in fashion, changing shape and ranging in height from hip-high to floor-length...

 for a garment, with a central double decrease

Decrease (knitting)

A decrease in knitting is a reduction in the number of stitches, usually accomplished by suspending the stitch to be decreased from another existing stitch or by knitting it together with another stitch.-Methods of Single Decreasing :...

 flanked by single increases

Increase (knitting)

In knitting, an increase is the creation of one or more new stitches, which may be done by various methods with distinctive looks.-Methods of Single Increasing :...

on either side.