The Kadena Air Base in Okinawa. There seems to be no consensus between Tokyo and Washington as to what percentage of the financial burden has been borne by Japan since 2004. | ISTOCK

How much does Japan pay to host U.S. forces? Depends on who you ask

Ahead of the visit to Tokyo by U.S. Defense Secretary James Mattis on Friday, the government appears to be missing a critical piece of information: How much does Japan pay to host U.S. military bases?

Tokyo has agonized over U.S. President Donald Trump’s attack on so-called host-nation support, Japan’s share of the cost of hosting U.S. military bases. Trump said on the campaign trail that Japan should pay more for the security umbrella provided by the U.S. military.

While news reports say Mattis is unlikely to demand more financial support during his trip to Japan and South Korea, there seems to be no consensus between Tokyo and Washington as to what percentage of the financial burden has been borne by Japan since 2004.

According to an annual report titled Allied Contributions to the Common Defense published by the U.S. Department of Defense in 2004, Japan provided direct support of $3.2 billion (about ¥366 billion) and indirect support worth $1.18 billion, offsetting as much as 74.5 percent of the total cost.

Even though the numbers were drawn from 2002 expenses, the figure has often been used by Japan in arguing that it’s paying a fair share. The figure was the highest among major U.S. allies at the time.

But last Friday, Defense Minister Tomomi Inada updated the information for the first time in more than 10 years, saying Japan paid about ¥191 billion in 2015, about 86.4 percent of the total cost.

Inada said the preliminary calculation did not include all related costs, implying that the number could be changed.

Meanwhile, U.S. Forces Japan told The Japan Times that the approximate cost of the U.S. presence in Japan is $5.5 billion, based on the 2017 Operation and Maintenance Overview by the Office of the U.S. Undersecretary of Defense.

It said Japan will pay ¥192 billion in the current fiscal year in direct support. U.S. Forces Japan said it does not attempt to calculate the percentage of burden-sharing.

Asked about the different figures, a Foreign Ministry official in charge of the Japan-U.S. security treaty said the ratio varies depending on which expenses are used to calculate costs, and that the ministry has no plan to issue its own calculation.

A Defense Ministry official also said that the U.S. usually does not want to crunch the numbers, as doing so would hint at who pays the most among the U.S. allies.