- Is it a good time to invest in the Yen?
in part it's a bad idea since contractionary policies are/will be implemented to slow its growth rate, but on the other hand it's great because it's value is constantly growing despite the implemented policies.
- does having negative interest rates means that people need to pay in order to keep their money in the bank? is this a contractionary monetary policy?
It appears from the news analysis that Yen has appreciated too quickly against dollars and policymakers are concerned. Implicitly, yen appears to be overvalued in the short run. It is never a good idea to invest in a currency that is expected to depreciate, i.e., lose value.
Yes, negative interest rate broadly means that lenders give more to get less. Negative interest rates are usually a result of too much liquidity in the financial system. A contractionary monetary policy reduces liquidity and raises interest rates.