If your seed geminated here is what it might look like, although looking at pictures online of a mature kishu tree I'm not sure that the seed I grew hasn't been crossed with something else or if the leaves will continue to change as the plant grows up
I missed this post earlier! Neither of my surviving mystery citrus look like yours, so I'm guessing they were from the half-dozen other things I put in that jar. I lost about 7 due to neglect (poor placement relative to the spray nozzles for my vacation watering system during an extended trip), but I do still have two that are doing pretty well now.
Here's one (oldest leaves first, then newer leaves), which I believe had only one embryo in the seed:
And here's the other one, which was polyembryonic, but the other ones didn't make it:
By comparison, here's a satsuma seedling, which actually looks closer to yours (makes sense as a mandarin), so I'm pretty sure neither mystery seedling is a satsuma: