The idiom "Da liegt der Hund begraben" means “that’s where the dog is buried,” and it’s used to indicate the root of a problem or the core of an issue. It’s similar to the English expressions “that’s the heart of the matter” or “that’s where the problem lies.”
It may sound strange at first, but the buried dog symbolizes something hidden, unpleasant, or forgotten that must be discovered to understand a situation fully. For example, if a company is struggling despite high sales, someone might say this idiom to suggest there’s a deeper issue at play—maybe poor management or internal conflict.
This is one of the more serious German idioms, often used in analytical discussions or to uncover hidden truths. Like many German idioms, it uses metaphorical language to make complex situations easier to describe in a vivid and memorable way.