I bought this tree last year at home depot for $20. It was labeled as "Osakasuki Sunrise" (spelled that way, wrong). I searched for that name sake and found nothing. When I bought it all the leaves had curled up and began to drop so I wasn't too sure on the fall coloring. So I have been curiously waiting to see what this thing does. Of course it was the last one to leaf out this year. When it finally did it was nothing like the Osakazuki I have. I really don't have any clue what it may be. I have attached a photo. So far I have had it in full sun, but am probably going to move it to morning sun this weekend. Attached is a a photo of my little trees just for fun. Here is what I have that has already leafed out before this one in question: Karasugawa Osakazuki Baldsmith Geisha Kamagata Burgundy Lace Shindeshojo Autumn Moon Corallinum Sango Kaku and an unknown Acer P.
Since there are over 800 different varieties of Japanese Maple, so its really hard to pinpoint the cultivar name from a couple of photos. I did look the name up in the 'World Checklist of Maple Cultivar Names' and it is not listed. Nor did a Google search find the name.