Mukayu has been Cupido's spiritual guideline during his most recent travels to Japan, resulting in his latest publication. The concept of mukayu is beautifully explained in a quote by the famous Chinese philosopher Zhuangzi, who lived 2,300 years ago: "An empty room will be filled with light because of its emptiness." Mukayu also refers to 'non-existence', 'not having a purpose', or 'things as they are'.