In its official submission to IAEA, INFCIRC/549/Add.1/16, Japan reported its plutonium holdings as of December 31, 2012.
According to the document, at the end of 2012 Japan had 4.4 tonnes of separated unirradiated plutonium at the reprocessing facilities, 2.9 tonnes in fuel manufacturing process, and 1.6 tonnes in unirradiated MOX fuel. Additional 0.4 tonnes of unirradiated plutonium is "held elsewhere." These numbers have not changed since the 2011 declaration.
In addition, Japan reported having 34.9 tonnes of unirradiated plutonium outside of its territory - 0.1 tonnes less than in 2010.
Japan also declared 133 tonnes of plutonium contained in spent fuel held at reactors sites and 26 tonnes - in spent fuel at reprocessing facilities. Some material, less than 500 kg, is declared as held at other sites. These amounts have not changed since 2011.
A more detailed account of Japan's plutonium holdings is contained in the annual report "The Current Situation of Plutonium Management in Japan", that was released earlier.