Originally Posted by
100% Green
Imperial Palace Gardens
Although you may have 18 hrs. at Tokyo, you will arrive at NRT around 3 p.m. Realistically you will reach center of Tokyo after 5 p.m. If you want to check-in to the hotel first to get rid of your luggage, which I recommend, it will be likely past 6 p.m. when you will be ready to explore Tokyo. 9 a.m. departure from HND means you have to leave the hotel to HND by 7 a.m., earlier if you are staying at opposite end of the city.
Considering your situation, likely Imperial Palace Garden will be close the time you are open to explore Tokyo.
Originally Posted by
100% Green
Tsukiji Fish Market
If your arrival at NRT is on Saturday then no go since the fish market is closed on Sundays. If your arrival at NRT is on Tuesdays, then the fish market is closed on many Wednesdays. Not closed on all Wednesdays, but looks like half of Wednesdays are closed.
Although Tokyo is one of largest metropolitan cities in the world, it is not 24 hrs. city. Many museums and gardens for tourists do close by 5 - 6 p.m., and many restaurants do close by 11 - 12 p.m.
Originally Posted by
100% Green
Meiji Shrine and/or Asakusa
Meiji Shrine closes the door at sunset, 6:00 - 6:30 p.m. summer time. The door opens at 5 a.m. in the morning. Many not fit your schedule.
Asakusa, the shops leading to the temple is open till around 8 p.m. Sensoji temple ground does not close but temple building close during the night.