I like your thinking ST........I had already considered using my forearm as a shield and then using the knife into the throat and then pulling the knife towards my body. It would be a close run thing as the bear is likely to shake its head when it bites thus breaking your arm and throwing you. I am less keen on your suggested grip which may be fine on puny human flesh but would likely have to much "flex" in the grip as you "push" the blade. Slashing motions would likely be just enraging to the beast. I like the concept of the blade facing me and pulling. Can you picture how much more stability and force that could be applied? You create a triangle of sorts and use the bicep for energy. I also like the idea of pointing the weapon at your adversary. All animals dislike pointy objects. Doubt that? Take your finger and point it at a dog and watch.....they will generally have some sort of modest but immediate reaction.

BTW.......if a black bear attacks you it won't be to punish you (mauling) like a grizzly will. If a black bear attacks you it is predatory......there will not be any lingering death unless he decides to eat while you are still kicking, then you get to watch like the woman geologist in Alaska who watched while both arms were devoured before a helicopter came to rescue her. She survived but both arms were amputated (as described in "Bear attacks, causes and avoidance"). 

Fearful? I must admit to the hair on the back of my neck standing on end the night the bear had us under a bit of siege that rainy night in Algonquin. When it "snuffled" near my arm with only a tent wall between us that got my attention in a hurry. It was the oddest thing.........My friend and I had so much heightened energy that it came out in intense suppressed laughter that actually started to hurt my insides. I know our faces were contorted from smiling and laughing although neither of us found our situation the least bit funny. The tarp dumping a half gallon of water every 20 minutes onto the side of the tent added to the fear and hilarity of the situation. It was surreal.......a tiny little light hanging from the tent ceiling casting an odd glow to the whole scenario. I eventually decided to go to sleep......my arms folded and a hatchet on my chest........My chum stayed awake most of the night with a can of bear spray in one hand and a small knife in the other.

On the other hand I have been plenty assertive with daytime contact.......probably a little to assertive. In the future I will probably stand off to the side and determine intent before I get fired up. In many cases that I have read the bear seems at first to be mostly harmless, puttering about, but then becomes more confident as time goes on.

I, for one, would not go solo without a can of spray....(I would't pack a firearm unless I was in polar bear country)...especially early in the year when their food sources are still light. Hunger is a big motivator. Intellect tells me I could likely live 10 lifetimes and probably never need the stuff.......but after reading about what can and has happened to folk I have no desire to be on the receiving end. It is basically a little peace of mind.........I have also wondered about how it would do against moose after having been chased a wee little distance (THAT will get your attention!!)...........and hey, what about a group of loud and unruly teenagers at midnight? Could be very effective  :D.