"吾唯足知 (Ware Tada Taru wo Shiru)", the Japanese word "Zen"
If each is read in combination with "kuchi", which the central word is meant to represent, then the characters become "吾唯足知".
These words kanji written on the surface of the stone are without significance when read alone.
The inscription of kanji combined with the square opening of the water basin: "Ware tada taru wo shiru". This is a Zen saying that can be translated as: "I know what 'just enough' is" or "I simply know what is enough".