When out walking Tanuki people often ask me if he’s an american akita. I think it is because when they think of the akita, they imagine them being red (and I just found someone posted a picture of him under the american akita tag on tumblr :p).
Generally people say one of the things that separates the two breeds is the american’s black mask, but many brindles have dark faces. They do have urajiro like the reds, but it shows in a lighter grey colour and not the clear white you see on the reds.
The white you see on Tanuki (dog on top) is not urajiro, but something called “Irish spotting” and is a remnant from the time all akitas were bred with other dogs. If you look at his legs contra his back, you can see that while his back is red, his legs are silver - that silver colour is the urajiro (now some brindles are actually silver brindles, but that’s a whole other story).
But for me the most striking difference is the size. The american akita is larger and more stocky (looks more like a bear), while the akita is lighter built and more “fox-like” in appearance.
There are differences in head shape as well, e.g. akitas have longer muzzle than americans.
I do understand that people mix them up, everyone can not be a dog geek.. but I think it would be so much easier to explain to people I meet if I had one of each. Or maybe not, people still ask if my “tiny” shiba inu is an akita.