Abstract. Three important physics issues for the ITER divertor design and operation are summarized based on the experimental and numerical work from multi-machine database (JET, JT-60U, ASDEX Upgrade, DIII-D, Alcator C-Mod and TEXTOR). (i) The energy load associated with Type-I ELMs is of great concern for the lifetime of the ITER divertor target. Recently, scaling studies of the normalized ELM energy loss depending on plasma parameters, such as the effective collisionality of the pedestal plasma and pedestal density fraction have progressed. In order to understand the physics base of the scaling models, the ELM heat and particle transport from the edge pedestal to the divertor is investigated. Convective transport during ELMs plays an important role in the ELM energy loss and heat transport to the divertor for high-density ELMy H-mode plasmas. (ii) Control of the divertor plasma and impurity ions is strongly influenced by SOL flow. Determination of the SOL flow pattern and the driving mechanism has progressed experimentally and numerically. (iii) Carbon erosion/redeposition are of great importance in particular for tritium retention via codeposition. Progress of understanding is reviewed.