Asian celadon? bowl/dish with blue/white interior

Chinese or Japanese? I really don't know, I know next to nothing about oriental items, so please pardon my ignorance.
What is the shape of this called....a bowl, a dish, something else?
Is the green coloring celadon?
Age?
Is this porcelain?
Anything else you can add would be fantastic, thanks in advance.
Measures approximately 2 1/4" high and 7" top diameter.
It has rust inside, can I safely use a rust remover for that?
There is what appears to be a chip on the top edge, which looks to have been smoothed and glazed over at the time of making....is that normal?, Is that bad?
I know....lots of questions...

 

u sure that's rust.....it looks like it was used as an ashtray !!

 

Yes, I'm sure. The picture does make it look odd though. Sorry

 

not a fault...just looks what it looks like from here...

 

Japanese, porcelain, celadon... Maybe Seto.

 

Thank you ever so much kard! I will look into Seto, much appreciated.

 

Kard, I'm curious why or how you may think it could be Seto? I read a bit about it on Goth but just wondering how to identify it? What would be the identifying factor? Sorry, I'm just clueless, and don't understand.
Any idea what to call the shape of this?
Thanks!

 

You might try making a paste of Barkeepers Friend using a scotch brite pad and elbow grease to remove the stains.

 

Thanks so much cluttered! I will try to pick some of that up today.