Tokyo Base
Tokyo Base was a Federation outpost that was located somewhere in the Alpha or Beta Quadrant.
In the 2360s, Kyle Riker worked out the Fuurinkazan battle strategies at this base. Afterwards, he was asked to come to Starbase Montgomery, where he would work as a tactical advisor to Starfleet, a position he accepted. (TNG: "The Icarus Factor")
This facility was only mentioned in dialogue.
In the Star Trek Encyclopedia, 3rd ed., p. 513, Tokyo Base was identified as a Starfleet facility.