The Q4 GDP number is available for Japan so here are the model updates including the new monetary and price level data. I've adjusted the Japanese core CPI for the VAT tax increases  in 1997 and 2014.
The prediction for Japan uses the same procedure as for the US predictions (see e.g. here), however I've integrated the inflation prediction errors to generate an error band for the price level (hence the size of the error will grow over time).
Here is the smoothed result:
And here is the prediction using the smoothed result:
Basically this prediction says inflation will be approximately zero for the next 10 years, barring any re-definition of the Yen.
 Here are the unadjusted versions: