The Ainu of Japan may only have 7-10% Rh negatives, but they stand out due to that frequency being more than 10 times that of the Japanese average.
https://rhesusnegative.net/themission/bloodtypefrequencies/japan/ainu/
That was according to the source I listed above more than 10 years ago.
According to the study below, 5% of the “pure Ainu” examined were Rh- and 0.56% of the Japanese were:
The Ainu are an indigenous people from the northern region of the Japanese archipelago, particularly Hokkaido.