First of all, I have to gush like an over caffeinated fan-girl and remind you for the third (fourth?) time that I adore this picture. I love the idea of a swordsman (ninja, samurai...etc) in the wintertime (my birth season and the season my two daughters were born in).

A few things that I noticed and I'm not saying you can fix them because it is, after all, a picture. You looked tense, it was probably very cold and it looks like you were on a slope albeit a small one. Maybe if you do a scene like this again you could try to relax more. I imagine the ground was cold so I'd suggest a towel or blanket you could park your rump on without anyone seeing it in the picture.

To me, it looked like you were trying a little to hard to relax. I imagine a winter swordsman who has just found a place for a rest would have put his sword against his shoulder so that his hands could tuck closer to him for warmth. Not that he had to look like he was shaking from the cold but even having them closer could have made it looked more relaxed.

That was it really. I adore this picture and the idea of the winter swordsman and if I could add it to my favorites a thousand times, I would. Maybe if you do more pictures the winter swordsman could find himself in a forest? (Though, you are probably in the city.) I hope this critique was helpful at least in some way.