"I've been running into this issue since the 1970s as a second-language speaker of Chinese. My wife, a native speaker of Taiwanese (whose parents, like most Taiwanese persons in their generation, were educated in Japanese under the prewar occupation of Taiwan by the Japanese Empire), tends to this day to confuse "green" and "blue" when speaking English. Those colors are both 青 in her mind."

I don't think this has anything to do with the Japanese. Historical Chinese poems often refer to 青天, ie "green sky". 青 is probably what we would call cyan, since there is another Chinese word for green - 绿.