I was happily browsing through the new Official Guide for Kendo Instruction; nodding sagely at the explanations of things I knew, when I reached the section on yuko datotsu. Having refereed internationally on many occasions and attended all the regional referee training courses, I like to think that I have a fairly clear idea of what constitutes ippon. My confidence started to waiver a little when I read the description of yuko datotsu for nito, particularly the explanation of ippon for the shoto.
Forgive me if I do not give the exact quote, as I am travelling without the book at the moment, but to score with the shoto the daito must be holding down the opponent’s shinai whilst the arm holding the daito (the long one) is fully extended. Now just to clarify this point, it means that the opponent’s shinai is being suppressed at a distance equating to the length of the arm plus a 38 shinai when you strike with the shoto (the little one). Now I am very far from being a nito expert. I have never tried it and have no intention to do so, but if I am not missing something, the rule makes it impossible to score with the shoto unless the player has a two metre arm or a telescopic kodachi.
I wrote about nito before http://wp.me/stBQt-nito and mentioned that I have never seen ippon given to a kodachi strike. I have also heard a variety of explanations from referee instructors and shinpancho about the difficulty of making yuko datotsu with the kodachi, because nito is “different from mainstream kendo”, but this makes it patently clear that the shoto is not meant for scoring with.