Otto Hackbarth began advertising his forked hosel putters in 1910, taking order by mail.  Chick Evans, the winner of the US Open and US Amateur in 1916, made it famous.  Evans used this club during a good portion of his career, and with great success.  Hackbarth wanted a center-shafted putter, but to help prevent the putter from twisting when putts were struck off center, he devised a forked hosel that would attach at both the heel and toe.  

This example is marked "Otto Hackbarth / Pat 687,539" on the sole, which is also inlaid with a lead weight.  The head, 34 1/4" shaft, and leather wrapped grip are all original.  This is a fine example of the Hackbarth Putter as the forks show no cracks (something commonly found with this club) and the head shows light use, with even wear to both the LH and RH face.

TCA2: V1 p 214-215