Traditionally, sumo is considered Japan's national sport. Japanese martial arts such as judo, karate and kendo are also widely practiced and enjoyed by spectators in the country. After the Meiji Restoration, many Western sports were introduced in Japan and began to spread through the education system. Japan hosted the Summer Olympics in Tokyo in 1964. Japan has hosted the Winter Olympics twice: Sapporo in 1972 and Nagano in 1998. Tokyo will host the 2020 Summer Olympics, making Tokyo the first Asian city to host the Olympics twice. Japan is the most successful Asian Rugby Union country, winning the Asian Five Nations a record 6 times and winning the newly formed IRB Pacific Nations Cup in 2011. Japan will host the 2019 IRB Rugby World Cup.