The genitive case is the case that shows possession and is expressed in English by the possessive "of" or an apostrophe ('s). The genitive case is also used with the genitive prepositions and some verb idioms. The genitive is used more in written German and is hardly used in spoken language. In spoken, everyday German, von plus the dative often replaces the genitive.
The first example uses the genitive to show possession.
This example shows how the same sentence would be spoken (with the genitive replaced by "von" and the dative).
The question you can use for the genitive is whose (“wessen”). Whose dog is it? It’s the man’s dog. Have a look at the table below to see how the articles change in the singular:
In the Genitive not only the articles change but also the endings of the nouns. Luckily the feminine nouns don’t change, so all you have to remember are the endings for the masculine and neuter nouns. If the noun ends with –en, -el, –er or a vowel you simply add an –s to the noun in the genitive. For example
If the noun is short and ends with a consonant you have to add the ending –es. For example: