The 12th edition of the Japanese Classification of Esophageal Cancer, published by the Japan Esophageal Society in 2022, is the first half of the English version. This edition updates the classification system to reflect recent advancements in diagnosis and treatment. Key changes include the elimination of "Ae" as an esophageal subsite and the introduction of "Jz" for the esophagogastric junction zone. The classification now includes subtypes for cT3 (resectable and borderline resectable) and cT4, with diagnostic criteria based on imaging techniques. The lymph node classification has been revised to align with the TNM system, emphasizing the number of metastatic nodes rather than their location. The staging system now includes clinical and pathological classifications, with a focus on preoperative treatment. The classification also addresses the management of endoscopically and surgically resected specimens, including detailed descriptions of surgical findings, endoscopic results, and multiple primary cancers. The edition includes new diagnostic criteria for esophagogastric junction cancer and updates the terminology for lymph nodes. The classification emphasizes the importance of accurate staging and treatment planning, incorporating prognostic data from the National Comprehensive Registry of Esophageal Cancer. The guidelines aim to improve the international use of the classification and provide a standardized nomenclature for esophageal cancer. The document includes detailed descriptions of tumor location, depth of invasion, and lymph node metastasis, along with diagnostic criteria for various tumor types and stages. The classification also addresses the impact of preoperative treatment on staging and prognosis, ensuring consistency with global standards. The edition reflects the evolving understanding of esophageal cancer and aims to enhance clinical decision-making and patient outcomes.The 12th edition of the Japanese Classification of Esophageal Cancer, published by the Japan Esophageal Society in 2022, is the first half of the English version. This edition updates the classification system to reflect recent advancements in diagnosis and treatment. Key changes include the elimination of "Ae" as an esophageal subsite and the introduction of "Jz" for the esophagogastric junction zone. The classification now includes subtypes for cT3 (resectable and borderline resectable) and cT4, with diagnostic criteria based on imaging techniques. The lymph node classification has been revised to align with the TNM system, emphasizing the number of metastatic nodes rather than their location. The staging system now includes clinical and pathological classifications, with a focus on preoperative treatment. The classification also addresses the management of endoscopically and surgically resected specimens, including detailed descriptions of surgical findings, endoscopic results, and multiple primary cancers. The edition includes new diagnostic criteria for esophagogastric junction cancer and updates the terminology for lymph nodes. The classification emphasizes the importance of accurate staging and treatment planning, incorporating prognostic data from the National Comprehensive Registry of Esophageal Cancer. The guidelines aim to improve the international use of the classification and provide a standardized nomenclature for esophageal cancer. The document includes detailed descriptions of tumor location, depth of invasion, and lymph node metastasis, along with diagnostic criteria for various tumor types and stages. The classification also addresses the impact of preoperative treatment on staging and prognosis, ensuring consistency with global standards. The edition reflects the evolving understanding of esophageal cancer and aims to enhance clinical decision-making and patient outcomes.