I was just on that 6am flight two weeks ago. I was invited to the Louis Tavern (?) lounge. It is between the D and G gates, I believe, and down one level from shopping. It is actually pretty close to the D7/D8 gates, which are often the departure location for this NRT flight. This lounge is not nearly as nice as the Thai lounge. I wish either Thai would open earlier, or UA would make that NRT flight a bit later! The Thai lounge is MUCH preferred!!! Anyway, the Louis Tavern (I think that's the name) is perhaps 24 hours??