I'm trying a Trig blade in a Merkur HD. The first shave worked out quite well. Today, my second shave was very different. my face was well hydrated, and I had a good lather from the same soap I've been using nearly every day. I went WTG and XTG as usual and it felt fine. Initial indications were that it was a normal uneventful shave, but a few hours later things were not good. My skin itself feels fine so it doesn't seem like razor burn, and it wasn't even a very close shave. If I rub my face WTG, there is no discomfort, but if I rub my face ATG, it feels like I 'm rubbing shards of glass into my face. I don't think the blade was dull since I didn't feel any pulling or drag, although the Trig didn't strike me as the sharpest blade on the first shave. Is this what is meant by blade smoothness? I really want to avoid this outcome, so I'm trying to diagnose the cause.