I wanted to suggest the idea, that perhaps Zen, with it's various subcategories, should perhaps be a main category in itself, rather than a sub-category of East Asian Buddhism.
It would seem the due to the Popularity and influence that Zen has as a main school of Buddhism in western culture, that it would make more sense to let it have it's own category, rather than call it part of "East Asian " Buddhism.
While, technically, it is part of East Asian Buddhism, in practicality, people don't think of it as a subject that way, any more than they generally think of Tibetan Buddhism as "Himalayan Buddhism", or "Central Asian Buddhism". While some may indeed call it that, in most practical contexts, it's generally known as Tibetan Buddhism, just as people generally think of Zen as Zen, and not a subcategory of other Asian Buddhisms.
This would seem to make more sense logically.
"Life is full of suffering. AND Life is full of the Eternal
IT IS OUR CHOICE
We can stand in our shadow, and wallow in the darkness,
We can turn around.
It is OUR choice." -Rev. Basil Singer
" ...out of fear, even the good harm one another. " -Rev. Dazui MacPhillamy