The Japan Airlines First Class Lounge is just past security, up a pair of escalators in Terminal 2 and is available to JAL first class
Sasidhar and I flew Japan Airlines when US Airways was doing the 120,000 mile first class roundtrip tickets. I actually finished this trip report a
Tokyo Station is one of two major train stations in the Japanese capital and the center for the Shikansen high speed (aka bullet) rail lines.