Instructions
Identify a Fairbairn-Sykes style knife. The Fairbairn-Sykes fighting knife is a double-edged knife. Look for a thin blade with the a small, round foil guard over the handle. The grip is rounded and thickest in the center with a slender neck three-quarters of the way toward the bottom.
Check the blade length. A Fairbairn-Sykes knife came in two different lengths. The first design had a 6 1/2-inch blade, while second and third design knives had a 7-inch blade.
Look for a ring grip. The William Rodgers Sheffield knife was the only Fairbairn-Skyes knife to have a protruding grip. If the knife is a Fairbairn-Sykes, a ring grip will indicate that is a William Rodgers Sheffield design.
Check for stamps. The second and third designs of the Fairbairn-Sykes fighting knife sometimes have "ENGLAND" stamps on the blade or butt. The William Rodgers Sheffield third design may also have "WILLIAM RODGERS SHEFFIELD" or "BROKEN ARROW" stamped on it.