No one should seriously believe that the BOJ would face any significant technical problems in inflating if it puts it mind to the matter, liquidity trap or no. For example, one can feel quite confident that if the BOJ were to issue a 25 percent increase in the current supply and use it to buy back 4 percent of government nominal debt, inflationary expectations would rise.
[T]he proposition that money issuance must raise the price level was false. Or if you like, it was missing a word: permanent money issuance would raise the price level. But a monetary expansion the private sector expected to be temporary, to be wound down after the crisis had passed, would do nothing at all: the extra monetary base would just sit there. Furthermore, it was reasonable for the private sector to assume that even large increases in the monetary base in a liquidity-trap economy would be temporary, to be wound down after the crisis had passed, would do nothing at all: the extra monetary base would just sit there
Given the way experience has undermined much of the original case for a 2 percent inflation target, and given the severity of the economic crisis, you might therefore have expected some revision – a rise in the inflation target, or a shift to some other kind of targeting – price level or nominal GDP targeting. But that hasn’t happened... This is quite remarkable. If the worst economic crisis since the 1930s, one that cumulatively cost advanced nations something on the order of 20 percent of GDP in foregone output, wasn’t enough to provoke a monetary regime change, it’s hard to imagine what will.