Irving Fisher, an economist who worked in the first half of the 20th century, called this the debt deflation trap.

ECONOMIST: Repent at leisure

But Japan must also act "to finally break free of the deflation trap" and it needed to "rely more on monetary policy to kick-start growth".

CNN: Lagarde warns over three-speed world

Japan seems to be stuck in a classic liquidity trap: it needs lower real interest rates to boost demand, but because of deflation they are stuck painfully high.

ECONOMIST: The new danger