The face of the Japanese people has changed significantly over the past 100 years. Japanese people around 1900 don't look Japanese. But they are definitely ancestors. Even the same DNA can change so much. The Japanese people have not been subjected to genetic disturbance from the outside for over 1,000 years. It's very homogeneous. The last time the Japanese people underwent large-scale genetic perturbation was from the 10th century BC to the mid-3rd century AD.