Japanese Black Pine - Pot Sizing

I have recently acquired a decent sized Japanese Black Pine which is currently in an Anderson Flat. It is ready to be repotted to a bonsai pot. My concern is not knowing if the pot I have is large enough and not having a store I can run to if I need something larger.

The tree height from the ground is about 40" and the Nebari is about 3-1/2 - 4". I have a rectangular pot which is 10-1/2" x 8-1/4" x 3-3/4" deep. I think it is large enough, but my “newbie-ness” has me second guessing. Should I have a larger pot on hand in the event I am not able to reduce to the put I have on-hand?


10” pot might be a little on the small side. I’d shoot for the same general proportions but at least a 12” pot.

For reference, I just took a similar sized tree (but not a pine) out of an Anderson flat and barely stuffed it into an 11” round.

Thanks. I ordered what I thought was 12", but they were referring to the outer dimension. Learning curve.