In the land of rising sun, stock prices are up and currency is down

In the land of rising sun(Japan),stock prices are up and currency is down.For the Nikkei has risen the most since 1972,yet the Yen against the dollar has fallen the most in five years.Accident? I think not,I know sound sophistic,but often weak currency lead to strong economic! How,because country can export it's produces a cheaper price,hence,making it more desirable for foreigners to buy their goods.Also,often a weak currency is cause by low interest rates which spur on consumerism in that country,and makes money cheap,by banks lending it cheap,hence,more plants factories and building leading to employment.Now down is inflation and also maybe the currency is cheap because people have little faith in country's economy.
Japan has two major problems:one an aging population,two debt.