So I'm a member of the SCA. This means that unlike a lot of artists who draw shields I have actually used one of these shields while fighting in armor (I'm not good at its. So it'ss not really bragging). but what I noticed that all the artist renditions of the shield showed the straps all wrong. in fact, the Viking shield had a metal or wood bar under that metal dome thing in the center. this allowed greater movement.
The other thing I noticed was that all the artist showed the shields in perfect condition. Ummmm yeah a good shield should look like a bone you gave to your dog last month.
So when I did this design I wanted to make sure that the shield actually looked like the owner had taken on an owlbear or two.