This was my first time properly doing a 1HDC (although I have been practising using closed ones before now) - quite a challenge!
My concept is a blade that pivots around the elbow, allowing use both in attack (pretty straightforward) and defence (to block oncoming swords etc).
Time was 59mins on my tablet laptop, plus an extra few mins adding the colour to the thumbnail page. Let me know what you think! 
Full size is here: http://www.hywelvaughan.com/wp-content/uploads/2011/10/1hdc01.jpg
Full size is here: http://www.hywelvaughan.com/wp-content/uploads/2011/10/1hdc02.jpg
