The 160-centimetre rule on the Shinkansen, and how to travel without your suitcase

A suitcase that clears an airline's check-in belt can still be the wrong size for a Shinkansen seat. The number to know is 160 centimetres, and it is not measured the way most travellers assume.

The 160-centimetre line

Add length, width and height together — three edges of the box, not the longest one. Under 160 centimetres total, the bag rides with you and nothing is required; most cases in the 60- to 70-litre range sit just under. Between 160 and 250 centimetres, the Tōkaidō, Sanyō, Kyūshū and Nishi-Kyūshū lines want you to reserve a 特大荷物 (tokudai-nimotsu, oversized baggage) seat in the last row of the car, where the space behind the seatbacks becomes yours. The reservation is free when you make it in advance. Boarding without one costs ¥1,000 and a conversation with the conductor.

The northern network — Tōhoku, Hokuriku, Jōetsu — has no equivalent requirement. This is why advice from a friend who ran Tokyo to Kanazawa does not survive the trip from Tokyo to Kyoto.

The constraint is not etiquette. It is three edges of a box, added together.

Hotel to hotel, overnight

Nearly every business hotel front desk, and most conbini counters, will take a suitcase and put it on a truck. Ask for 宅急便 (takkyūbin), hand over the next hotel's name, address and phone number written in Japanese — a printout of the booking confirmation does the job — and expect roughly ¥2,000 to ¥2,500 for a medium case on a route like Tokyo to Kyoto. Hand it over before early afternoon and it usually lands the following day. Hokkaidō and Okinawa take longer; ask at the counter rather than assuming.

This is why so many people on the platform are carrying almost nothing. Moving 手ぶら (tebura, empty-handed) with a daypack turns Kyoto Station's stairs, the tight transfer at Shin-Ōsaka and the last gravel hundred metres to a ryokan back into walking. Pack one night of clothing into the daypack, since you and the case travel on separate schedules.

荷物は先に送り、身ひとつで列車に乗る。

What the lockers are actually for

Coin lockers run about ¥400 to ¥800 depending on size, and the large ones at major stations are taken by mid-morning on weekends. Newer banks accept Suica, Pasmo and Icoca: you touch the same card to open the door, so keep that card with you and keep it charged.

For anything a locker will not swallow, look for the staffed 手荷物預かり (tenimotsu-azukari) counter — Tokyo, Kyoto and Shin-Ōsaka all keep one near the main concourse, usually a few hundred yen per bag per day, with a fixed same-day pickup deadline posted at the window. It is the honest answer to the gap between an 11am checkout and a 7pm train.