If you check the Internet re: transferring luggage in Japan, for example at
http://www.japan-guide.com/e/e2278.html, you will find a description of a service which is reputed to be inexpensive and reliable. Here is an overview from that site:
Takuhaibin is a convenient service for sending parcels, luggage and various other types of goods from door to door nationwide. Delivery is usually on the next day, and costs are moderate.
Yamato Transport started the service in the 1970s and remains the market leader with their Takkyubin service. Although it is a registered trademark, Takkyubin commonly also refers to takuhaibin services in general. Other major companies include Sagawa Express (Sagawakyu) and Nittsu (Perikanbin).
Tourists with a lot of luggage can consider takuhaibin as a means to send their luggage from the airport to a hotel or between hotels, in order to avoid hauling heavy luggage onto crowded trains and up and down stairways.
From Tokyo to Kyoto or Osaka, shipping a medium suitcase is about 2000 yen, or a little less than $17 US at current exchange rates. I gather you can make arrangements through the hotel, although there are counters in Airports and I understand many convenience stores are agents. We're going to stick with the hotel arrangement.
