Preserving the Writer's Voice
The first and second reformulations preserve the writer’s voice by keeping the passive construction It is said in Japan. The Oregon State University video Writing Across Borders explains that one characteristic of Japanese writing is that writers state things less directly than is the custom in the U.S., and Japanese readers are expected to work harder than U.S. readers to follow the writer’s meaning. The passive construction seems to match the way a Japanese L1 writer might express herself in her native language. If I were the writer, I might favor the second reformulation, which preserves the writer’s voice with the phrase It is said in Japan, while changing the clunky phrase represents how intelligent people are to the phrase is a sign of intelligence, which flows more naturally in English. As a native English speaker, I like the third reformulation the best because it most closely resembles the way I would express the idea myself, using an active rather than passive construction, but it really loses the Japanese writer’s voice.