Greetings My Good Netizens -
The first published reference I can find to a two-handed grip ( basically the isoceles ) was in the book "Shooting To Live"
published in in 1942 by Captain William E. Fairbairn and Captain Eric Anthony Sykes. Both had served extensively in Shanghai Municipal Police department, and Fairbairn was well-known for his work in cleaning up the Triad Gangs in Shanghai ca 1900. Many of his encounters were running fights in alleys and "house-clearing" exercises.
Faribairn was a proponent of point-shooting, hip-shooting, and two-handed shooting, as well as teaching hand-to-hand fighting and knife fighting. He was using and teaching the technique long before the book was published to a variety of military, police, and special agencies. You may also remember him for his training of knife and stick fighting and the famous "Fairbairn Commando Knife".
Rex Applegate was a student of Fairbairn, and also promoted the 2-handed isoceles triangle hold in the U.S.
In spite of it's proven efficacy stodgy beaurocrats and armchair generals insisted on continuing to teach the one-hand method.
Jack Weaver (LAPD) modified the "isoceles hold" into a more dynamic "bent-elbow isometric" two-handed hold and used it to great effect in Cooper's tournements.
Whilst I am certain others used it prior to ~1900, I can find no documentation to that affect.
yhs
prof marvel