When I refer to government spending and money-printing I am talking about fiscal policy, which can produce inflation if not counterbalanced by taxation. The BoJ, like any central bank, sets monetary policy in response to inflation (and expected inflation) and will raise interest rates if inflation increases; this is what "implements monetary policy with the aim of maintaining price stability" means. Although most central banks, the BoJ included, consider price stability to be a state of low inflation, not necessarily zero inflation.
