Visited the Tsukiji Market early in the morning. We were able to walk through the market even though it was supposedly wasnt open for vistors until after 9 AM. You can walk through and nobody will bother you as long as you behave yourself. There is a wide variety of seafood available for sale and you will be amazed with what is edible.
We also stopped for Sushi. The queues were very long by 5:30 AM for the famous sushi places so we settled for the Donburi dished and they were very good.
Highly recommended for the food and photo opportunities.
The Tokyo Municipal Building was close by so this is a good opportunity to get two free sights in the same morning.