The Japanese word for this service is "Takkyubin" - If you search for "Takkyubin" on flyertalk, you will find oodles of information.

If you're talking about sending bags from the airport when you arrive in Japan - There are Takkyubin counters in the arrivals halls at all airports, which will provide the necessary address labels / forms etc. and take care of delivering your bags.

If you're talking about sending bags from a hotel - virtually any hotel will have the wherewithall to arrange a Takkyubin delivery. (Ask at front desk).

If you're not staying at a hotel, you can arrange Takkyubin delivery from most convenience stores.

It is also possible to send bags to the airport - the Takkyubin companies operate counters to allow you to collect your bags in the departures halls of all the major airports.

Like I said - there's oodles of information on Takkyubin if you search this forum.