Based on the results of the recent Japan Clinical Oncology Group( JCOG) 0802 trial, thoracic surgeons will have more opportunities to perform segmentectomy for primary lung cancer soon. Segmentectomy requires a high level of skill due to the importance of accurate anatomical understanding and proper intersegmental plane formation. This procedure involves the precise identification and dissection of anatomical structures within the lung, which is more complex than lobectomy. However, techniques such as pulmonary vein taping and pulmonary artery dissection are fundamental procedures that extend from those required for lobectomy. These techniques must be performed with great care to ensure patient safety and optimal outcomes. Surgeons must perform meticulous surgery by understanding the correct anatomical layers in daily practice, as this knowledge is crucial for avoiding complications and achieving successful resections. Additionally, variations in the courses of intersegmental veins, bronchi, and pulmonary arteries necessitate careful preoperative computed tomography( CT) image interpretation. Understanding anatomy from multiple angles, such as from the ventral and dorsal sides, is important for segmentectomy, as it allows for a comprehensive approach to the procedure.