The Bank of Japan continued its spending spree on government debt, although the pace of increase has slowed dramatically since the introduction of yield-curve control in September 2016.

The central bank owned 39.5 percent of Japan's bonds and Treasury bills, up from 13.1 percent when Haruhiko Kuroda took over as governor in March 2013, according to its quarterly Flow of Funds statistics released Tuesday.

The BOJ cut the amount of short-term debt it owned, while increasing bonds. The pace of bond purchases slowed, showing how the bank has stealthily tapered its buying, even while it has kept its stated purchase target unchanged.