The automotive sector in Japan is dominated by Toyota and has therefore one big bond issuer which has still a good rating. Second to this company Honda has to be named. More on the sideline is Mitsubishi. All other names are not pure Japanese car manufacturers any more.
Even with the current turmoil in the automotive sector Toyota is still a valid choice. For Mitsubishi the situation could get more challenging. In the long run there will be only two big Japanese automotive companies left.