It is relatively difficult to detect minute depressed (0-IIc) and flat (0-IIb) type early gastric cancers (EGCs) with ordinary endoscopic observation. Good preparation and washing out the mucus in the stomach are necessary for detection and correct diagnosis with chromoendoscopy using indigocarmine. It is important to diagnose whether EGC infiltration is submucosal (SM) deep or not, because the indication of endoscopic resection depends on the depths of the EGC. The characteristic endoscopic features of SM deep invasion in EGCs are related to macroscopic type, tumor size, histological type, fold convergency and endoscopic rigidity of the lesion area.