Some sort of nondescript Japanese or Korean Maple. Hard to say there are hundreds upon hundreds of different cultivars. What color does it leaf out in spring? Autumn colors? grafted?

My money is on Acer Pseudosieboldainium, Korean Maple, with a level of

certainty of about 3%.

hahah! leaves turn orange and fall off.

thank you!

Based on the leaf size, I'd lean very heavily to Acer palmatum. Korean maple leaves are about twice that size. It is also more heavily lobed than a Japanese maple - 9-11 lobes compared to a JM's 5-7 (and rarely, 9) lobes. Tree in question has only 7 lobes.