Otto Hackbarth began advertising his forked hosel putters in 1910, taking orders by mail.  Chick Evens, 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 Hacbarth / Pat 687,539" on the sole, but the lettering is now either faint or unreadable in places.  The head, shaft, and grip are all original as is the lead inlay in the sole.  In used condition, this putter is solid, with no cracks in the forks as is often the case, and it still presents well.

TCA2: V1 p 214-215