This is a simple form of woven stitch technique. It is usedΒ in drawn or pulled thread embroideries commonly. Woven bar consists of weaving between two sets of laid threads.

woven_bars_1 woven_bars_2
Fig 1: Make straight stitches horizontally. Fig 2: Bring the needleΒ out through A, a point on the side, to begin the weaving. Now, take the needle over and under three laid threads at a time, as shown. Then, turn around and repeat the process.Β Do not pluck the fabric underneath. The only time the needle goes through the fabric is at the strat and end of the whole process.
woven_bars_3 Fig 3: A finished portion of woven bar loks like this.