Past, present, future: unattainable,
Yet clear as the moteless sky.
Late at night the stool's cold as iron,
But the moonlit window smells of plum.

Hakuin Ekaku (1686 CE-1769 CE), Hakuin Ekaku was one of the most influential figures in Japanese Zen Buddhism and regarded as the reviver of the Rinzai school, refocusing it on its traditionally rigorous training methods integrating meditation and koan practice.