Hi Dobbersky, That video from YouTube is ok, but that is not a good example that you are looking for. The basic movement is moving forward positioning the front foot. As for nagashizuki the only thing outside your sensei that I can say is that I think you should not consider it the kata that strict. Off course, in the kata move straight forward, put your foot down on a diagonal line and let the body follow. As you say moving diagonal - tending to step out to the left - is wrong, it is wrong for the kata, but practically you can position the front foot wherever you like. The dynamic of the "landing foot" of nagashi zuki is the same as the landing foot of the 2nd move of torimi in kihon kumite ipponme. To me, it is a principle of bodymovement rather then a strict punch that needs to follow the kata. edit: As we use mats, lines of the puzzle stucture are there. I always tell my students that the ball of the foot should stay on the same line when moving forward even after the taisabaki. So the front foot moves forward in a straight line and the ball of the foot remains on this line, the heel and body moves off.