Cancer is scary because it is difficult to treat, painful, costly, isolating, etc. It puts heavy pressure on individuals and families from physical, psychological and social aspects. However, in the initial stage of cancer development, it is very curable, but in the past, the means of detection and identification were limited, right? Nowadays, despite the rapid technological progress, not all cancers can be diagnosed at an early stage, but three types of gastrointestinal tumors, namely esophageal cancer, stomach cancer and colon cancer, can definitely be detected and cured early if you are willing to undergo screening. First of all, conventional gastroscopy, gastroscopy can detect more obvious lesions when observed from the throat to the duodenum, but for the diagnosis of early cancer, it was not until the emergence of NBI technology with magnification that a qualitative change was made. With technical note: Endoscopic narrow band imaging is an emerging endoscopic technique with the advantage of being able to precisely observe not only the epithelial morphology of the GI mucosa, such as the epithelial glandular recess structure, but also the morphology of the epithelial vascular network. This new technique can better help the endoscopist to distinguish the epithelium of the gastrointestinal tract, such as the intestinal chemosis epithelium in Barrett’s esophagus, the altered vascular morphology in the inflammation of the gastrointestinal tract, and the irregular alteration of the glandular recesses of early tumors of the gastrointestinal tract, hence the name electronic staining endoscopy. However, NBI alone is not enough; it must be combined with magnification imaging to bring revolutionary advances. NBI mode can be used for: (1) early detection and diagnosis of microscopic lesions; (2) combined with magnification endoscopy to observe their fine structure, further evaluate their characteristics and predict histopathological findings; and (3) as a means of targeting biopsy and endoscopic treatment of lesions. The application of NBI technology has greatly improved the diagnosis and detection rate of early cancers of the middle and lower pharynx, esophageal intraepithelial carcinoma, Barrett’s esophagus, early gastric cancer, and early colon cancer. the color contrast ratio of blood vessels and mucosa in NBI images is significantly greater, which makes it easier to observe and evaluate the morphology of esophageal epithelial microvasculature (IPCL), especially for inexperienced endoscopists to detect lesions. Compared with the histological gold standard, the evaluation of IPCL using NBI endoscopy is up to 85% accurate in predicting the depth of tumor infiltration; therefore, the Japanese Society of Endoscopy recommends that HR-NBI should be routinely used in screening tests for esophageal squamous carcinoma. I have often watched NBI before coming to Japan, but I did not find it to be so awesome or so well studied by the Japanese. It is so damn useful in the esophagus for finding suspicious lesions, in the stomach for determining the distinction between early cancer and inflammation, and in the colon for making surgical plans. We used to do gastroscopy to find early cancers, but on what? In most cases, if the tumor does not progress deeper, it will be reported as suspicious cancer or atypical hyperplasia, which delays clinical treatment. However, it seems that the relationship between NBI and pathology has been studied very thoroughly in Japan, and it is possible to accurately determine the grading and staging without pathology just by looking at NBI, and I don’t know if it is really that accurate or they are just bragging, but at least it is clear where the most suspicious and suitable pathology is taken under NBI!