Seiko SNM017K1 Samurai "The Ninja" - Limited Edition 021/500 (2006)
There is also a limited black dialed series SNM015K1 of 500 pieces

Just in case
you are trying to buy one of these on the bay, the pictures showing all links as provided by the factory. Please note that there is a interesting long end-piece next to the clasp, you will see it more easily in one of the pictures of the resized Ninja.