I'd be willing to be a bit flexible on standards given Ume material isn't very common in the states. Unless the price is astronomical the cost could easily be offset by propagation if you're in the right zone and willing to put in a bit of labor to sell rooted cuttings off. A fairly modest, shohin one was listed on the auctions page this week for a 575 buy it now price. Kind of shows the degree of scarcity one is dealing with when it comes to Ume. My only concern here would be seeing the leaves closer, the "tongue" on the leaf doesn't look very profound and It'd make me think it might be a native Prunus species like americana.