"Shifts in Income Inequality and Social Class Dynamics" 

1. Income Distribution Trends in Japan: How do you think income distribution trends in Japan compare with the shifts observed in Western economies like Spain, Italy, and Germany? Have there been similar changes in the presence of various social classes within different income quintiles in Japan?

2. Role of Capitalists in Japan: The study notes a downgrading of capitalist households in Spain and Italy, while Germany shows an upward shift for capitalists in higher income quintiles. How might these trends mirror or differ from the current situation of capitalist households in Japan?

3. Wage Dynamics in Japan’s Top Income Brackets: The study found varying trends in the share of wages among top earners in different countries. How do you think the presence of wages among Japan's top income earners compares? Has there been a noticeable shift in the contribution of wages to Japan's top income distribution?

4. Social Class Dynamics and Income Sources in Japan: The study indicates that in Western economies, wage earners’ income remains predominantly wage-based, while capitalist households derive more from profits and self-employment. How would you assess the income sources across different social classes in Japan, particularly in terms of wage-based income versus profits?

5. Application of the Income Factor Concentration (IFC) Index in Japan: The study uses the IFC index to measure the concentration of income sources across income distributions. How might applying a similar index to Japan's economy reveal trends in income inequality and class concentration? Would you expect the results to align with the findings in Western economies?