"Sharpen this side"?

[Seraphim]

I just recently recieved a nice vintage Craftsman strop that has two horsehide components, and no cloth strop.

One of the leathers says "sharpen this side", and indeed it has higher draw than the "finishing side", my question, is: was the "sharpen" side originally treated with some form of abrasive, or was/is it simply higher draw?

Any vintage experts out there?

 

[mdunn]

im no expert, but ive seen (and heard of) strops with one side impregnated with an abrasive that I suppose make them like a pasted strop