For each bag the total of the length, width and height must not exceed 250 centimetres, the length must not exceed two meters and the weight must be no more than 30 kilograms. Luggage pieces less than 160 cm (sum of height x length x width) can be brought aboard without prior reservation.

On the Shinkansen (bullet train) between Tokyo and Osaka, you can bring almost any standard suitcase, but you must follow the "160cm Rule." If the total dimensions of your suitcase (length + width + height) are 160cm or less, you can bring it on board without a reservation and store it in the overhead racks or in front of your feet. If your bag is between 161cm and 250cm (typically very large "checked" style suitcases), you are required by law to reserve a "Seat with Oversized Baggage Space" in advance. These seats are located at the back of each car, and there is no extra fee if you reserve them in advance. If you bring an oversized bag without a reservation, you will be charged a 1,000 yen penalty and may be asked to move. Any bag larger than 250cm is strictly prohibited. By 2026, it is highly recommended to use the SmartEX app to book these specific seats, or use a "Hands-Free Travel" luggage delivery service (takuhaibin) to send your bags directly to your Osaka hotel for about 2,000 yen.