The Iwashimizu form does ring a bell, maybe I read it somewhere. But my notes say:
Lilium leichtlinii col. Japan 4347-year collected 2008
Japan: Ooyama Toyama Prefect 300m orange-red,50cm
I had forgotten that this would be the var. maximowiczii, since it is orange-red. Further, there is more discussion as to whether this form is really a leichtlinii at all! To me, what's important is that it is the wild form.
I also have several seedlings started last year, collected wild from a much colder area, and again I assume var. maximowiczii:
Japan:Yamanashi Prefect 1500m orange,70-80cm
I'll be very interested to see what yours looks like, too, Della.