How blade width (not thickness, but width) relates to slashing ability?  Lynn Thompson referenced this briefly in a video but did not elaborate and I would like to understand better.

Thanks for your help.

Wider blade will no deflect as easily. It would tend to slash in a straighter line.

Thanks.

Width is not as critical to slashing ability as edge profile is.
One of the things that made the traditional Katana such an incredible slashing weapon is the edge profile.
A hollow grind or straight grind is less effective than a convex grind, which tends to push the material being cut away from the blade.

Wider blade = more drag.  In addition, the finish also has an effect on drag - rough, "painted" finishes have a lot of drag.

Wow, this is more complicated than I realized.

Drag is your answer. But width is probably a bit anal unless we're talking about something sticky.

eta, or really out of the ordinary.

Slashing is a nondescript word when it comes to swing cuts. Instead think slicing and chopping. It comes down to the tool and intent. I think flat grinds are better for pocket knives, and sabre/convex grinds are better for fixed blades.

For instance, scalpels are not thick convex grinds because they need to be swift, precise, and deep without the inertia of weight. Axes aren't thin flat grinds because they need to displace what they're cutting with weight and inertia.

Think a 5.56 armor piercing versus a 12 gauge slug. The grind of a blade is similar to the ballistic coefficient of a bullet.

The wider the blade (ie distance between the spine and cutting edge) then the finer the blade can be ground when using a Full Flat grind.

Basically a knife is a triangle. If the spine is 3mm thick, and the cutting edge is 0.5" away, then much the blade it will be fairly thick, which will increase cutting resistance.

Whereas if the spine is 3mm thick, and the cutting edge is 1.5" away, then much of the blade above the edge will be quite thin, making it cut with less resistance.