The Genitive case is most often used to indicate possession. Let's take a look at some examples:
Colloquially, you can say:
But this sounds more elegant:
Die Katze von Anke.
Ankes Katze.
Der Computer von Max.
Max' Computer.
Die Bücher von Andreas.
Andreas' Bücher.
If the name ends in -x, -s, or -z we simply add an apostrophe and no -s.
Oh, it's like English then!
Almost...
Very important:
Unlike English, you can only use -s or an apostrophe with proper names:
Das Vaters Haus. Das Haus des Vaters.
The father's house.
And, of course, we have to adjust the articles to express possession.
I knew it...
Genitive definite articles
der → (masculine)
Das Auto des Vaters. The car of the father.
das → (neuter)
Das Fahrrad des Kindes. The bike of the child.
die → (feminine)
Die Regeln der Schule. The rules of the school.
die → (plural)
Die Bücher der Kinder. The books of the children.
Also here you could replace the genitive with von. But von is a dative preposition and is always used with dative articles! - Das Auto vom Vater. (= von dem Vater) - Das Fahrrad vom Kind. (= von dem Kind) - Die Regeln von der Schule. - Die Bücher von den Kindern.
This is often the case in spoken German. When writing, however, one tends to use the genitive, as it sounds more elegant, but both are possible and grammatically correct!
So if I'm feeling lazy, I can just use the dative?
Yes! You have spent so much time practicing the dative already, so you can use it as a backup.
There are some common expressions that use the genitive. You'll see these every once in a while in everyday life.
The world's most beautiful place. → Der schönste Ort der Welt. Remember that Welt is not a proper name, so you cannot use the apostrophe here: Der Welt's schönste Ort. This is the house of my dreams!
→ Das ist das Haus meiner Träume!
The best holiday of your life!
→ Der beste Urlaub deines Lebens! "Album of the Year" goes to... → "Album des Jahres" geht an...
Someday we will visit Munich.Eines Tages werden wir München besuchen.
Eines Tages is often used in stories and fairy tales, just like once upon a time.