Can anyone explain how 'stimulus / response' appears in Chinese or Japanese Buddhism?

- Can anyone explain how 'stimulus / response' appears in *Chinese* or *Japanese Buddhism* ? - What does it mean? I can recall barely nothing about it, but I do know that it features in Zhiyi's work, *Chin Fa-hua-hsüan-i * at least. I'm especially interested in how the terms, which I believe are paired, may have a universal meaning.