Please refer the following information just in case you have to get to the hotel by yourself instead of taking the pick-up service should be provided by the organizer.
1) Airport Limousine Bus: This should be the easier way to access the hotel, since the bus takes you directly to the hotel entrance.
1-1 From Narita: Approximately 120-150 minutes to the hotel (Fare: 3,100 JPY)
1-2 From Haneda: Approximately 60-85 minutes to the hotel (Fare: 1,230 JPY)
2) Railways: This could be a little bit complicated. You have to transfer the trains and, once you get off the train at Shinjuku Station,
you have to walk from the station to the hotel (*the underground passengers' way) for 8 minutes.
Please refer to the following websites to find your way by railways:
GETTING TO SHINJUKU FROM NARITA AIRPORTS
GETTING TO SHINJUKU FROM HANEDA AIRPORTS
SHINJUKU WASHINGTON HOTEL: LOCATION (*including the map from the stations to the hotel)
Shinjuku (新宿) is one of the 23 city wards of Tokyo, but the name commonly refers to just the large entertainment, business and shopping area around Shinjuku Station.
Shinjuku Station is the world's busiest railway station, handling more than two million passengers every day. It is served by about a dozen railway and subway lines, including the JR Yamanote Line. Shinjuku is also one of Tokyo's major stops for long-distance highway buses. A large bus terminal, named Busta Shinjuku, is conveniently located on top of the railway station.
Shinjuku Gyoen (新宿御苑) is one of Tokyo's largest and most popular parks. Located just a short walk from Shinjuku Station, the paid park's spacious lawns, meandering walking paths and tranquil scenery provide a relaxing escape from the busy urban center around it.