The HISSATSU is a combat knife conceived with some advanced and interesting features. This knife was sent to me around 1997-1998 by ANCIENT EDGE which, at the time, was solely marketing this weapon which is made of a very dark gray color, possibly polymer. At the time I was told it was used by troops at Desert Storm.
Knife specs:
Blade length: 7 inches
Handle length: 4 7/8 inches
Kissaki: 4 inches
Blade thickness at Mune: 7 mm tapering towards the kissaki
Overall length: 12 3/4 inches
Blade finish: industrially done stock removal with a bevel edge that is very sharp.
Do not know if is heath treated but tend to believe it is. The HISSATSU I own has been put to plenty of testing throughout the years and it shows no defect whatsoever.

There are two main features that make this knife quite unique and both are located at the scabbard or saya. Being inspired by a Japanese tanto, the HISSATSU  carries no habaki. Instead, there is a little screw in the scabbard that allows for a stronger or lighter hold of the knife to the scabbard. Apart from this feature there is the quick release belt clip allowing the knife to be carried according to the user's preference.

 Another feature is the scabbard shape, aiming at not interfering with the remaining of the equipment. Note the little protuberance or the inherent inwards curve in the area where the habaki should be and how it relates directly to the little screw which, as said, controls the tightness of the scabbard. This I consider a very important feature in holding the knife in place.

The three parts that compose the HISSATSU. Also note that the handle's emulation of samé does provide for a good grip in this modern aikuchi style tanto. There is also a hole at the scabbard tip to tie it to the leg or body for extra-safety (not interfering with the rest of the equipment).

The way I personally like to carry a combat or operations knife is like this. And this knife allows me plenty of choices.

Drawing the knife couldn't be simpler. Depending on one's stance, the movement could even be concealed. I always use a back-grip.

The scabbard mechanism also allows for the knife to be carried this way, which is another variation depending on the characteristics of an operation and what are the weapons to be carried.

Again this allows for my preferred back-grip draw. As the knife slides out quietly it can be concealed immediately under the forearm or the index finger can help in the rotation of the blade for the blade's tip to be pointed frontward.

From the small array of combat knives I own, some pictured here, the HISSATSU comes up as superior to all others in my opinion.

 Antonio Cejunior BLADESIGN