> [ . . . ] it seems that the kanjivg vectors
> were derived from a Japanese schoolbook font. Does that mean that they
> don't actually correspond to any current digital font?
Japanese Schoolbook fonts are also called Kyokasho fonts. As model fonts for KanjiVG, DFKyoKaSho-W3-MP-RKSJ-H by DynaLab and A-OTF Kyoukasho ICA Pro L by Morisawa and Company Limited have been used. The Morisawa font was used for example, when the DynaLab font was lacking characters.
Japanese Schoolbook font forms are some sort of mixture of Kaisho and Mincho characters. If for example a stroke is slanted in Kaisho and vertical in Mincho, a Schoolbook font will use the vertical stroke. KanjiVG also contains normal Kaisho versions of characters which differ in Schoolbook fonts.
To my knowledge, Mincho fonts have much less variations of character forms than older historic writings. Probably their Chinese versions, the Ming fonts, may have more variations too, as in your examples.
Without doubt it would be worthwhile to do more research in character forms, their usage and a better abstract description. I am planning to do so, as soon as I have time.
By the way, our lab for Japanese studies at Tübingen now has a new second assistant for our computing needs. She is Chinese, and probably, she will be of help to adapt KanjiVG for Chinese character forms, too.
We also had a Japanese intern for four weeks and she prepared several hundred new characters for KanjiVG. Element description is still missing, but we hope to be able to include these characters in KanjiVG soon.
Best wishes
Ulrich