Blood is perfectly easy to work out once you have the system memorised. It's not difficult to mark or learn, though of course it requires practice. It is quick and there is no counting, only an interpretation of the markings. That said, I do personally find that it is a little difficult to see and the deck has to be too close to my eyes to be comfortable for my liking. It's fine if you can show them their card in front of your face, not so fine if you hand them the deck to cut in their hands.