A recent Japanese thread titled "Even After Seeing This, You Can Declare Anime Characters Japanese?" (これを見てもアニメキャラは日本人って言い切れるかい？) picked up this issue once again, trying to suss out the physical characteristics of anime characters and whether they can be identified as Caucasian or Asian (here, Japanese).
Back in 2010, blogger Julian Abagond asserted, "The Japanese see anime characters as being Japanese. It is Americans who think they are white." Largely, I agree with this. When Japanese see anime characters, they think they are Japanese—even if they have purple hair or blond hair—or they don't even think about it that deeply. It's often only when the characters have exaggerated Western figures or speak goofy Japanese that viewers are clued in that they are looking at a non-Japanese character.
What's more, this latest thread seems to confirm it. The title alone, "Even After Seeing This, You Can Declare Anime Characters Japanese?" implies that when Japanese people look at anime characters, they naturally assume that said characters are Japanese.
As evidence in this thread, there are several images that attempt to show what it's like when anime characters have white facial features.
For example, this image states that beautiful female anime characters have Caucasian features. It compares "a true Japanese" (本来の日本人) to an "anime Japanese" (アニメの日本人) by contrasting things like the length of their necks and legs, the shape of their legs and back, etc.
The image is largely drawn, no pun intended, on stereotypes—an unflattering one for Japanese females, too. It also assumes that all Japanese and Caucasian women fit this paradigm. That simply is not true for either group.
This image shows what Sakura from Naruto would apparently look like if she were drawn as a Japanese character by contrasting well-known Japanese celebrities, such as a young Utada Hikaru, with Caucasian models—instead of comparing Japanese models with Caucasian models.
One commenter online accused the images of intentionally picking unflattering images of Japanese to prove this point—an argument I agree with somewhat! While the Japanese images don't show idealized traits, the white ones do, assuming the Caucasian default is beauty. As, well, a white person, I can attest that this default is simply not true!
Moreover, many of Japan's top fashion models have the same idealized features found in the beautiful "anime Japanese". Does that make them white? That notion seems rather insulting.
And this image redraws several anime and manga characters as "Japanese" by doing things like changing the width of noses and the size of the lips. As with the images of women, the construct is based on stereotypes—here a default image of a Japanese male and a Caucasian male.
So are these characters white? Are they Japanese? One forum user replied, perhaps offering the best answer, "They're anime people." That they are, that they are.