The Shinkansen (Japanese Bullet Train) has a generous baggage policy, but it features specific rules regarding "oversized" items that were strictly enforced into 2026. Each passenger is permitted to bring up to two pieces of luggage, with each bag weighing no more than 30 kg (66 lbs). The total dimensions (length + width + height) of each bag cannot exceed 250 cm. Crucially, any bag with total dimensions between 160 cm and 250 cm is classified as "oversized" and requires a mandatory, though free, advance reservation on the Tokaido, Sanyo, and Kyushu lines. If you board without a reservation for an oversized bag, you will be charged a 1,000 yen penalty fee and may be required to move your bag to a different area. Small and medium suitcases (under 160 cm) do not require a reservation and can be stored in the overhead racks. Items like strollers, musical instruments, and sports equipment are generally exempt from the oversized reservation rule, though they still count toward your two-bag limit.