You said "horizontal striking motion." If you meant vertical strike (a horizontal strike wouldn't make sense from an "over one's head" starting position), you're probably referring to what is often called a shomengiri or shomenuchi. Starting from the upper posture known as jodangamae or jodan-no-kamae, this is a powerful posture. It's true that jodan is often an initial position, but it can also be a secondary position. One avoids creating an opening when assuming jodan through timing, distance, and strategy (what the opponent is doing at the time.) Also, a shomenuchi needn't only be done from a static posture; one can quickly move from one strike to another, or from a low posture into a shomenuchi.
"I always come to the conclusion when I play it out in my head of me or someone else getting cut about 2 or three times in the middle of retracting the blade." After getting some training under a qualified sensei, you can "play it out" for real with a shinai or bokken. I think you'll see that, when used appropriately, your opponent will not have an opening in which to cut you two or three times when shomenuchi is used appropriately. See for example: https://www.youtube.com/watch?v=3PVrq4i4iSc and https://www.youtube.com/watch?t=165&v=_6X7G7T8vL0
Last edited by Brian Owens; 11th May 2015 at 20:32.
Yours in Budo,
---Brian---