Which lines need a reservation
The rule applies to the Tokaido Shinkansen (Tokyo to Shin-Osaka), the Sanyo Shinkansen (Shin-Osaka to Hakata), the Kyushu Shinkansen (Hakata to Kagoshima-Chuo) and the Nishi Kyushu Shinkansen. Other lines such as Tohoku or Hokuriku do not require it, but space is still limited.