The Japanese Classification of Gastric Carcinoma, 3rd English Edition, published by the Japanese Gastric Cancer Association, provides a comprehensive system for classifying and recording gastric cancer findings. The classification uses uppercase letters (T, N, M) followed by Arabic numerals to indicate the extent of disease. The clinical classification (c) is determined before surgery, guiding treatment selection, while the pathological classification (p) is based on additional pathological evidence and provides prognostic information. The classification includes detailed descriptions of tumor size, location, macroscopic type, histological type, depth of invasion, stromal volume, infiltrative pattern, and capillary invasion. Lymph node metastasis is categorized by anatomical location, and distant metastasis is classified as M1 disease. The classification also covers treatment evaluation, including surgical and endoscopic resection margins, residual tumor status, and response to preoperative therapy. For resected specimens, the document outlines the preparation, fixation, sectioning, and histological diagnosis process, emphasizing the importance of accurate documentation and measurement. The classification is designed to provide a standardized approach to the diagnosis and management of gastric cancer, aiding in clinical decision-making and therapeutic planning.The Japanese Classification of Gastric Carcinoma, 3rd English Edition, published by the Japanese Gastric Cancer Association, provides a comprehensive system for classifying and recording gastric cancer findings. The classification uses uppercase letters (T, N, M) followed by Arabic numerals to indicate the extent of disease. The clinical classification (c) is determined before surgery, guiding treatment selection, while the pathological classification (p) is based on additional pathological evidence and provides prognostic information. The classification includes detailed descriptions of tumor size, location, macroscopic type, histological type, depth of invasion, stromal volume, infiltrative pattern, and capillary invasion. Lymph node metastasis is categorized by anatomical location, and distant metastasis is classified as M1 disease. The classification also covers treatment evaluation, including surgical and endoscopic resection margins, residual tumor status, and response to preoperative therapy. For resected specimens, the document outlines the preparation, fixation, sectioning, and histological diagnosis process, emphasizing the importance of accurate documentation and measurement. The classification is designed to provide a standardized approach to the diagnosis and management of gastric cancer, aiding in clinical decision-making and therapeutic planning.