Attendance at the Tokyo Motor Show used to be mandatory for the world’s carmakers. At this year’s show, which opens later this week, there will be only three, all niche European manufacturers. The only leading car makers among the 108 exhibitors are Japanese firms like Toyota and Honda. The 45-year old Tokyo show has been eclipsed by Shanghai’s as Asia premier auto show. April’s show in Shanghai attracted 1,500 exhibitors from 25 countries, reflecting China’s emergence as the world’s largest car market.