In Internal Martial Arts, Issue #6 (out of print - I don't know how to purchase today, in case anyone asks)
Tetsutaka Sugawara: Aikido and Taiji by Jayson Chung . . .Modern martial arts are too stiff, TS feels, and, unfortunately, Aikido is not an exception. As an example, many Aikido teachers focus on the use of the hand as a blade (tegatana), but TS feesl this is too limitiing. "We should use all our surface in training, not only this edge," he said. "If the hand is hard, the palm is tight, you cannot feel anything."
Interesting discussion. I have a copy of TS' second volume on Aikido and Chinese Martial Arts - Weapons training. Some very nice concepts there.
I selected the above quote from Ellis' original post because it stood out to me. Of course I cannot know in detail what expression of tegatana TS was referring to in his article, but I disagree on the premise that the use of tegatana is inherently limiting due to the hand being "hard".
Tegatana study and application is a core of Tomiki's Aikido and it is quite well developed to become a primary point of sensitivity that one uses to detect and effect subtle movements and changes in an attacker's mental and physical state. Well-developed tegatana skills allow one to detect these changes at any point of contact with ones partner or attacker and exploit these changes as needed.
I will agree with TS however that one cannot see tegatana as merely the outer edge of the handblade. All aspects of the surface must be used. This skill is important in developing "tekubi okoshi", which is seen by some as a point of initial development in understanding a particular expression of aiki that Ueshiba is known to have used in the 1930s. This is that skill to direct the force of a grab or push directly back into the centre of the attacker along his straightened arm and nullify his force, collapse or project him. The option one uses depends much on control of the tanden, spine and the ability to soften or harden sections of ones tegatana accordingly imho.
In my own practice I have found that tegatana allows me to sense the motion of my partner/attacker quote quickly and in conjunction with proper tai sabaki I am able to exploit motion and execute kuzushi in a very powerful but relaxed manner, constantly receiving new input as the dynamics of the attack changes, so contrary to TS' view it is not limiting at all imho.
Just a few thoughts.