We have started clinical application of 8K ultra-high definition (UHD; 7680 x 4320 pixels) technology to a rigid endoscopic system for advanced minimal invasive surgery. Our 8K UHD endoscopic system consists of an 8K UHD camera head with a lens adapter, rigid endoscope, xenon light source, 8K UHD monitor, and 8K UHD recorder. The first model of an 8K UHD camera head was developed based on a broadcasting camera in 2014, and the weight was 2.2 kg. The second model of an 8K UHD camera head was our original achievement in 2016, and the weight was 450 g. In 2017, we finally succeeded in developing the world’s smallest 8K UHD camera head of 370 g weight for mass production. We were able to achieve clinical success using the first model in two cases of cholecystectomy in 2014. Furthermore, after downsizing and weight saving of the 8K UHD camera head, we performed four cholecystectomies with higher maneuverability in the abdominal cavity using the second model in 2017. These experimental and clinical studies revealed the engineering and clinical feasibility of the 8K UHD endoscope. The 8K UHD endoscope promises new possibilities for intricate procedures including anastomoses of thin blood vessels and identification of thin nerves, as well as more confident surgical resections of various types of cancer tissues. We believe that our 8K UHD endoscopic imaging is very likely to lead to major changes in the future of medical practice, not only in typical endoscopic surgery but also in new heads-up surgery.