Blade is clearly marked. The edges are so flat that the blade is almost sharp. There is a small dent on one end of the blade (looks like it was hit with a sharpener). It's square (that's why I had to replace my old combo square!). My only real complaint about it in use is that it's quite difficult to get the notch on the blade and set screw to line up properly once you remove the blade completely. again to collect it. If you often detach the blade or flip it to switch between metric and imperial units, you probably won't like this square.