For readers unfamiliar with the subleties of golf club construction, cavity back irons are, as the name suggests, irons that are hollowed out behind the clubface. Their design allows manufacturers to remove weight from behind the clubface and distribute it around the perimeter of the clubhead. Thus, cavity back irons typically have a wider sole, a lower centre of gravity and a larger sweet spot than the competing ‘blade’ style of iron.
The history of cavity back irons can be traced back to 1959, when Norwegian émigré Kartsen Solheim, working in his garage in Redwood City, California, discovered that by redistributing weight from the back of the clubhead of a putter to the heel and toe reduced rotation of the club and produced a cleaner, more consistent strike. Indeed, the sound of the clubface striking a golf ball was the origin of the ‘Ping’ brand name.
One of the earliest cavity back irons, the Ping Ballnamic 69 – a traditional, forged iron, with two cavity slots behind the clubhead – was introduced in 1961. In 1966, Solheim resigned from his job at General Electric to establish Karsten Manufacturing and continued to experiment with peripheral weighting. The first recognisably modern cavity back iron was the Ping Karsten 1, which was introduced in 1969. Investment cast – that is, created by pouring liquid metal into a hollow ceramic mould – from hardened stainless steel, rather than forged, the Karsten 1 featured a single, deeped cavity, positioned close to the heel than the toe of the club, barrel hosel construction and peripheral weighting.
Generally speaking, cavity back irons are more forgiving than blades. The lower centre of gravity makes it easier for beginners and higher handicap players to get the ball in the air sooner, while the perimeter weight makes it easier to hit the ball straight.