The previous post reviews the Japan Airlines first class lounge in the main building of Terminal 2. That is the larger and primary first class lounge for Japan Airlines. If connecting or originating at Narita you will encounter that lounge first after clearing immigration. I would suggest using that lounge until time for boarding your flight.
However if your flight is leaving from the Satellite Building and you want to be close to the departure gate, Japan Airlines has a smaller first class lounge in that building, too. This lounge has fewer services but is no more than a six-minute walk from any gate in the Satellite Building.
The seating in this lounge is similar to the main lounge.
This lounge is divided into smaller spaces that offer more intimate and private settings compared to the main lounge.
The Satellite lounge has a TV, which I do not recall seeing in the main lounge.
The eating area in this lounge is larger and nicer than the eating area in the main lounge, and the buffet and beverage selection are equivalent with premium beverages and Japanese and Western cuisine.
This lounge has individual pieces of sushi on the buffet instead of a sushi bar.
There are showers but no massage or shoe shine services.
You can enjoy views of the gates and taxiways while waiting for a flight.
The Japan Airlines first class lounge in the Satellite Building is a great place for a short stay before a flight.