Endoscopic diagnosis of gastrointestinal early neoplasia is divided into three steps: detection, characterization, and preoperative diagnosis in order to determine the proper treatment strategy. In the field of early gastric cancer, substantial evidence of chromo- and magnifying-endoscopy has accumulated for constructing guidelines. In this lecture, I will show the technique and the knowledge in order to achieve curative treatment based on the most updated scientific evidence regarding early gastric cancer. If every endoscopist can learn the content in this lecture, the correct and precise diagnosis can be made for the safe and curative treatment of early gastric neoplasia.