Japan and the United States intend to change the location of a training area for the U.S. forces in waters off Chiba Prefecture’s Boso Peninsula, it has been learned.

The training area currently restricts the passage of commercial flights using Narita Airport. The government thus concluded it is necessary to adjust its location as part of efforts to prepare for an increasing number of visitors expected to come to Japan for the 2020 Tokyo Olympic and Paralympic Games.

By adjusting the location, the government will likely be able to press ahead with its plan to add 40,000 arrival and departure flights to Narita Airport’s annual slots.

The adjustment plan will be finalized at a meeting of the Japan-U.S. Joint Committee — a bilateral body to consult over the operation of the Japan-U.S. Status of Forces Agreement — slated for this month.

The area will be moved to a new location this summer, and the change will be permanent.

The adjustment will apply to the Charlie water training area and R116, the airspace above it. Both, located southeast of the Boso Peninsula, were set after the end of World War II.

As the U.S. Navy uses them for anti-aircraft and anti-ship live-fire exercises, among other purposes, heavy restrictions are placed on the passage of private fishing boats and commercial aircraft in the vicinity.

Currently, the number of arrival and departure slots at Narita Airport stands at 300,000 annually. The government plans to improve taxiways and strengthen the flight control functions at the airport in order to add 40,000 flights sometime after late March 2020 to prepare for the 2020 Tokyo Games.

In the future, the government aims to bring the number of slots to 500,000 annually by building a third runway.

When the airport becomes overcrowded due to an increasing number of flights taking off and landing, airplanes that cannot land immediately need to be put into a holding pattern in the air.

Under the current circumstances, the airspace allowed to be used for such aircraft is limited due to the Charlie water area and R116, making it difficult to increase the number of arrival and departure flights.

Under the envisaged adjustment, the training area will be moved several dozen kilometers to the south from its current location to minimize the impact on flights using Narita Airport.

The government compromised with the U.S. side by suggesting slightly expanding the size of the training area following the location adjustment.

At the upcoming meeting of the Joint Committee, the two countries are also expected to finalize an agreement to allow Japan to control some commercial flights passing through airspace currently controlled by the U.S. Yokota Air Base in Fussa and neighboring municipalities in Tokyo. The airspace stretches over Tokyo and several prefectures.

A plan to expand the number of international arrivals and departures at Tokyo’s Haneda Airport is also underway to prepare for the Tokyo Games.

With Japan in charge of some flight controls, the operation of planned new routes for flights landing at Haneda Airport can be realized.

The government has set a goal of raising the number of foreign visitors to 40 million by 2020, having reached 31.19 million in 2018. To achieve the goal and make the Tokyo Games successful, it is necessary to operate Narita and Haneda airports to the fullest extent. With the envisaged adjustment of the training area, the government has made necessary arrangements with the United States for both airports.