I went looking for cows 10 and 12, since I knew roughly what area to look in. I found cow 10 without too much trouble, it was at street level opposite cows 9 and 11, and open to the footpath, but in a corner under a recessed building entrance.
After about 15 minutes looking for cow 12 I broke down and checked the map, which showed it was in the Kokusai building. Even then it took me another 10 minutes to find it, since it was in the basement (there are about a dozen restaurants down there).
Cow 10
Close-up of cow 10
Close-up of cow 10