My wife uses sissors

The last loaf I made was a very wet dough and I knew it was going to be difficult, so I used sissors. It worked pretty well but the slashes were shorter, the sissors don't expand enough so you can't get the long slashes you want. They still wanted to stick, so after the first snip, I dipped them in water and that worked better. Next time I'll try wetting the razor blade and see how that works.

I use a razor blade held as horizontal as possible.

So I ended up going all Freddy Krueger on the 1st loaf with lots of slashes. Though I was thoroughly exasperated by it, the loaf actually turned out beautifully as it ended up splitting at the top and along some of the slashes. For the second loaf, I tried a slow surgeons type cut which made a deep cut in the top. For some reason with this loaf the slow cut seemed to work better. The 2nd loaf wasn't as 'artistic' as the 1st, but it worked. Has anyone ever used a pair of scissors to just snip cuts on the top? I think otherwise next time I'll have to try slow and horizontal with this type of loaf (it is the Tartine Country Loaf). The fancy french razor is quite sharp and brand new so I'm sure this was not the issue. Thanks to all for your suggestions!

My serrated bread knife. And speed. And practice.

I use either a single-edge razor or a serrated knife. If the dough isn't moist after its last rise--if there's a slight crust--spritz it with water or an egg wash. Hold the blade so that it's almost horizontal to the top of the dough. Slash as fast as nutcake says: Zip, zip, zip. Pop it in the oven.

You can also use a serrated blade, just make small, quick slicing movements. If you want to use a sharp paring knife that works well too. I would not buy that Grignette (name of the tool) unless you want to get decorative. A razor blade will do the trick too.

I'm on the "quick slash" side of the discussion. And I also own that tool...

Do it quickly--just slash it I find that as quick as possible and go deep works best. I even do it with a serrated knife.

A razor blade.

This is a tricky one, but try dipping your blade in a bit of oil before and also I find that if I cut at an angle and go a little deeper than normal, it's a heck of a lot easier. I still need a lot more practice at it myself...frustrating, I know...hang in there!!