The plane running between two adjacent pulmonary segments consists of a very thin layer of connective tissue through which the pulmonary vein also runs. To perform an anatomically correct segmentectomy, this segmental plane needs to be divided. Before the operation, the locations of vessels and bronchi are confirmed by three-dimensional computed tomography. A 4-cm minithoracotomy skin incision is made in the fourth intercostal space on the antero-axillary line, and two ports are added for the scope and the assistant surgeon. Dissection is performed bluntly with confirmation of the pulmonary vein. If the segment is divided along the anatomically correct segmental plane, the pulmonary parenchyma in the residual segments is not compressed by the stapler and inflates fully without deformity. The divided intersegmental planes fit together completely, thereby closing small air leaks. The goal of a segmentectomy is to preserve the pulmonary parenchyma to retain its function. However, resection of a central segment such as the ventral segment (S3) of the left upper lobe by the stapler leaves small shrunken segments and markedly reduces the volume of the residual lung. An anatomically correct segmentectomy by blunt dissection can be performed with correct division of the segmental plane, and no fibrin glue or biomaterial sheets may be necessary.Introduction The goal of a segmentectomy is to preserve the pulmonary parenchyma to maintain its function. However, resection of a central segment such as S3 of the left upper lobe by a stapler leaves small shrunken segments and markedly reduces the volume of the residual lung. To perform an anatomically correct segmentectomy, the segmental plane needs to be divided by blunt dissection with confirmation of the pulmonary vein. If the segment is divided along the anatomically correct segmental plane, the pulmonary parenchyma in the residual segments will not be compressed and will fully inflate without deformity. Air leakage from the segmental plane can be corrected with absorbable thread sutures, and any small air leaks are closed due to the close fitting of the divided intersegmental planes.