Thanks for the submission. I like overall form. Would prefer a colored logo in a white background. Prefer the style of Entry #7, though the karate technique shown in #8 is a better form. Entry #8 hides the technique too much. I like the kanji characters. A black belt could be a nice accent. Arm positions in Entry #7 are a bit uncontrolled. Something like these arms would be better (one arm out in front a bit bent, one near the body, almost ready to launch upon landing):
http://whatthehealthmag.files.wordpress.com/2011/11/karate.gif. That's a flying kick in that picture (don't want that). A roundhouse or thrust kick from the ground would be good.