The chapter analyses and compares the development of two types of contribution-based pension systems in four countries, thereby contrasting Bismarckian pension systems (South Korea, Vietnam) with pension systems that rely on national provident funds (Sri Lanka, Malaysia). Although all countries are facing considerable problems in expanding effective coverage and providing a decent pension after retirement, they have undertaken considerable political efforts to maintain or even expand those systems. We explain this outcome through a modular and mechanism-based approach, highlight six complex causal mechanisms—the outcompeting mechanism, the gaining acceptance spiral mechanism, the evasion mechanism, the double benefit mechanism, the crisis management by going further mechanism, and the alarmed middle classes mechanism—and show when and how these mechanisms unfolded in the four countries.