On the Shinkansen (specifically the Tokaido line), you are allowed to bring up to two pieces of luggage, each weighing no more than 30 kg (66 lbs), with total dimensions (length + width + height) not exceeding 250 cm. However, there is a specific rule for "Oversized Luggage" (bags between 160 cm and 250 cm). If your bag is oversized, you must reserve a specific "Oversized Luggage" seat in advance. There is no extra fee for this reservation if booked ahead of time, but if you board without a reservation, you will be charged a 1,000 yen penalty and your bag may be moved to a remote area. For the short 15-minute hop between Osaka and Kyoto, many travelers find it easier to use a "Takkyubin" (luggage delivery service) to send bags directly to their hotel for about 2,000 yen, or simply use the overhead racks for standard carry-on sized bags (under 160 cm total), which do not require any special reservation or extra fee.