I've posted a picture of the results of that cut, in the hope of getting some good advice. I stepped into Jie with a suibu and had the back of the sword braced with my hand at point of impact and beyond. The main question is whether the edge angle (highlighted with waterproof mascara for easy viewing), is steep enough. In the form, this cut is fairly vertical. If it's possible to tell, from viewing the picture, how can I improve the direction of my Jie cuts?

Also, it's worth saying something about wet ground when employing stepping movements into cuts. I suppose Chinese soldiers would have been working on slippery ground too. I'm not quite sure how to be completely safe while stepping quickly into a cut, with a very sharp sword, on ground that is already wet. Comments?