Jal and china airlines baggage on separate tickets

I currently have a flight on JAL from NY to SGN with a layover in HND, but our end destination is TPE. We would like to book a separate flight from SGN to TPE on china airlines but not sure if our baggage can be checked thru all the way. has anyone have any experience with a flight connecting thru Vietnam regarding Visa and checked bags?

thank you and appreciate any advice