On the Shinkansen (Japanese bullet train), you are officially permitted to bring up to two pieces of luggage, provided each bag weighs no more than 30 kg (66 lbs) and the total dimensions (Length + Width + Height) do not exceed 250 cm. However, there is a crucial "160 cm rule" you must follow: if any single bag has total dimensions between 160 cm and 250 cm, you must make a specialized "Oversized Baggage" reservation. This reservation is free if booked in advance with your seat, but if you board without one, you will be charged a 1,000 yen penalty fee. For 2026, this rule applies to the Tokaido, Sanyo, Kyushu, and Nishi-Kyushu lines. Bags under 160 cm (standard carry-ons and medium suitcases) do not need a reservation and can be stored in the overhead racks. Any bag exceeding the absolute 250 cm limit is prohibited entirely and should be sent via Japan's efficient "Takkyubin" luggage delivery service.