Bill Tindall
Nowhere in the Kato-Kawai papers studied to date do they claim that they invented using a cap iron to control tear out. To the contrary, they approach their studies as though what they call the "cap iron effect" was common knowledge.

They never state this theme explicitly, but it appears to me that their series of papers in the technical journals were focused on extending the life of the blade in planing machines by choice of metal, coating the bade with an abrasion resistant material, (vandadium carbide for example) or taking advantage of normal wear to achieve self sharpening.

Additionally, these professors taught at a a university where trades teachers are taught. Additional publications are focused on teaching future teachers the technical aspects of planing. To this end they have publications covering preparation of the plane sole, sharpening, the planing video, setting the cap iron, etc. It is these papers that will be of most interest to us and they are the hardest to get copies of because they were published in less widely circulated journals. However, I am in contact with Professor Kato and he is sending a DVD with copies of these papers. Without additional translation help it will be quite some time to get them all translated.

In one of these publications the professors describe how to optimally set the cap iron by examining the shavings (sounds a bit like what Warren describes except the professors provide pictures to aid the teaching). Keep in mind, this publication's objective is teaching, not discovery.