This review considers the microstructural evolution during sintering, which involves the pinch-off of pore channels and the formation of closed pores, from a point of view of mechanics. The microscopic shrinkage, i.e., the relative motion of adjacent particles, is driven by the sintering force and the mechanical force transmitted by the contact. The concept of sintering force, which has been proposed originally for sintering of two particles, is extended to the sintering of multi-particles. Here, we focus on the sintering by coupled grain boundary diffusion and the surface diffusion, which is the most important mechanism for sintering of fine powders at relatively low temperatures. We show that the shrinkage rate of a closed pore is also proportional to the sintering force. The mechanics of sintering in particle-scale will help to understand the relationship between the microstructure and the continuum mechanics of sintering [ABSTRACT FROM AUTHOR]