If the underlyinggrowthrate of productivecapacity had remainedthe same, this would imply that the economy was operating around 10% below itspotentialoutput.
The rise in inflation suggests that the economy is already operating well above capacity, so growth will need to be slowed more sharply to below its trend rate.
Rather than the tumbling yen being more evidence of economic incompetence, the exchange rate is the mechanism that redistributes demand away from economies that are operating at full capacity towards those in recession.