Haneda airport in Tokyo is officially called Tokyo International Airport. It was the gateway for Japan till Narita airport was opened in late 1970's. Then, Haneda turned to domestic airports which hosts the most busiest route on Earth, Tokyo-Sapporo. All international flights were departing/arriving at Narita, which had a tremendous troubles and arguments when its opening. The left wings activists supported the landowners not to sell their lands to authority. There is still a private land which is surrounded by Narita airport. Then, Narita airport had strict security controls for people to entry the airport, checking left wing activists or not.
Narita airport was notorious for its distance from city center of Tokyo. The government tried to build shinkansen between Tokyo station and Narita airport but the plan was abolished due to the Japan National Railway's huge deficit. JNR later broke up into 7 JR companies which has no economic ties among them. When the tourists increase and neighboring countries as like China and Korea have enjoyed the economic growth, the capacity of the Nartita airport was in danger. It happened due to there was just a single runway due to landowners who did not sell their lands. Then, Japanese government realized that the Narita airport is not sufficient for them even increasing the runways, therefore they started to expand Haneda airport and reopened as international airport again. However Haneda still limits their flight numbers according to open sky policies between Japan and other countries.
Now you can fly to Haneda from following cities in Europe: London/Paris/Frankfurt/Munich.
Then, other options are to fly to Dubai or Doha by Emirates or Qatar Airways.
If you have Japan Rail Pass, you can take the Tokyo monorail without any supplement.