Vietnam Airlines from Tokyo to Bangkok has 1 flight every day. And there are 7 flights per week flying out of Tokyo which connect to Bangkok.
The price for economy class – one way ticket of Vietnam Airlines from Tokyo to Bangkok is 34.212.000 VND (or ~$1709 USD) and the price for bussiness class – one way ticket of Vietnam Airline is 48.506.000 VND (or ~$2423 USD).