I came across one youtube video of wild Japanese primrose in "Senju-ga-hama", some isolated shore of Chuzenji Lake in Oku-Nikko. Most of people who see the video could be impressed, and would make wish to visit the place someday. This youtube video is made in 2012 by http://www.discovernippon.jp/index.html
Unfortunately, when I found the video, the season of the flower was already over. However, I could not wait for the next season and made a day trip to Nikko on sunny weather day during the rainy season, having expectation to encounter to the flower. Although I could see only remained flowering spots, I enjoyed viewing the lovely flower and the nature of Oku-Nikko so much. Please join us to come to this heaven.