Trees, Shrubs and Conifers: Growing a Gingko Biloba 'Jade Butterfly' in Container, 0 by Mipii

Mipii wrote:
I agree with Wee, it looks like a graft line and the branch below the graft line looks like it has slightly different leaves (without the 'butterfly split'). If you want a reverted variety, one of the parentage of your cultivar then air layer it to grow some roots of it's own and cut it off. If you don't want another Ginko Biloba then cut it off just beyond the collar so it will heal nicely.

Either way, cut it where depicted in the photo (I had to briefly borrow your photo, but you can have it back now).