Arisaema sikokianum, or Japanese Jack-in-the-pulpit, was first featured on Botany Photo of the Day a decade ago: Arisaema sikokianum. I made mention in that entry that I photograph this species almost every year in the Garden; that isn’t so true anymore, but it was pleasant to revisit photographing it this past May.
Other common names include Shikoku cobra lily, Japanese cobra lily, and snow rice-cake plant. It is indeed native to Japan, where it is known to hybridize with another Japanese species, Arisaema tosaense.
North American and European Garden use of Arisaema sikiokianum has noticeably increased over the nearly two decades I’ve known of the species; it has even been deemed a Great Plant Pick (of relevance to local gardeners).