The friendship between gentlemen is plain like water, and therefore enduring.
A proverb from the Zhuangzi, meaning that true, wise friendships are not flashy or overly emotional but are calm, pure, and lasting, like water.
The saying 'The friendship between gentlemen is plain like water' teaches that true friendship is unpretentious.
Standard kanji spelling of the proverb, using ごとし.
Variant with 如し instead of ごとし; slightly more literary or archaic feel.
From the Chinese classic Zhuangzi (荘子). The phrase contrasts the pure, lasting friendship of virtuous people with the cloying, self-interested relationships of lesser men.