Chef's Knife BolsterThe bolster is the thick shoulder of heavy steel located at the front of the handle where it meets the spine, or the top (non-cutting) edge of the blade. In addition to balancing the knife, the bolster also helps keeps your fingers from slipping while you work, thus preventing hand fatigue and blisters.
Not every chef's knife will have a bolster. A bolster indicates that a knife has been forged from a single chunk of steel, as opposed to being stamped out of a roll of sheet metal. These stamped knives are generally inferior to forged knives. The thickness of a bolster shows how thick the original chunk of steel was — and the thicker, the better.