Fear for low birth rate and hyper inflation and Gereman balanced budget policy

Fear for low birth rate and hyper inflation and Gereman balanced budget policy. Previously thought that German long-going and unchallenged balanced policy came from hyper inflation after WW1, but now need necessity to see the relationship with low birthrate at those periods. It makes a dramatic contrast with Japan's failure to maintain the policy after "Oil Shock and stagnation" while they didn't have experienced low birthrate in inter-war  period.