ALL SOLD OUT!! YOU GUYS SHOULD BE GETTING THEM SOON!!
YouTube - How to Filet a Fish (Mahi Mahi for Sushi)
YouTube - How to Filet a Fish (Yellowfin Tuna for Sushi)
A few specs:
Overall Length: 14.25"
Blade: 9.5"
Full tang, single bevel on the right. Stainless steel with wooden handle.
Info on bevels: http://www.watanabeblade.com/english/special/hunt.htm
How are they sharpened?
The Japanese use a water (wet) stone. They usually start off with a coarse or medium grit stone, then finish off with a fine stone. Obviously the more fish you filet the more you'll need to sharpen it. With average use the edge will stay for a pretty long time.