写信人在河这头收信人在河那头
[xiĕ xìn rén zài hé zhè tóu shōu xìn rén zài hé nèi tóu]
Translated as 'The letter writer on one side of the river, the recipient on the other'. A romantic and literary metaphor representing separation but also a bridge between two people via letters, evoking nostalgia and sentimentality about distant communication and longing.