How do I use the genitive case? It seems less common.

The genitive case indicates possession or belonging. It's less common in spoken German, where von + dative is often used instead, but it's essential for formal writing and certain expressions.

Rule The noun in the genitive case (the possessor) takes -s (for masculine/neuter singular) or -es (if ending in s, ss, x, z, or for clarity). Feminine and plural nouns don't change their ending in the genitive. The article changes according to the table above.