In Japan this species is called; gengorou. Much years ago this name was also used for males of us Japanese. This species was very common in Japan and surrounding countries but now it is getting to difficult to find, especially in cities and there suburbs. In some parts of the mountains this species can still be found in large stillwater which has rich water plants and no naturalized creatures, but only with some luck. With a length of 40 mm they are the biggest Japanese water beetles.