As in any culture, doctors are a high-profile profession in Japan. To become a medical doctor, you must pass the national medical exam (医師国家試験) and get a medical license. After getting your license you are required to have 2 years of training as an intern.

The pass rate of the exam is said to be around 90% so the bar may seem low. However, the prerequisite is that you have to get a 6 year medical degree. In Japan, getting into college is the hardest part, especially medical school.

Once you get the license, it is valid for life, and there are no re-certification courses or anything. So while an elderly doctor may have lots of experience, they may not be up to date on the latest practices and technology. And of course, young doctors do not have as much experience, so that’s a trade-off.

Also specialties are not specified in Japanese medical licenses. Therefore, an internal medicine doctor can decide to perform surgery one day without any additional certification. But I think they tend to stay in their court. Why take the risk, right?