marş

/marʃ/

Cases

SingularPluralWhen to use it
nominativemarşthe marchmarşlathe marchesthe plain dictionary form — the doer of the sentence
genitivemarşnıthe march'smarşlanıthe marches'the owner — whose it is
accusativemarşnıthe march (as the object)marşlanıthe marches (as the object)a specific, known object — whom or what
dativemarşhato the marchmarşlağato the marchesdirection or recipient — to where, to whom
locativemarşdaat / in the marchmarşladaat / in the marcheswhere it is; also having — mende bar, "I have it"
ablativemarşdanfrom the marchmarşladanfrom the marcheswhere it comes from; also "than" when comparing
When to use each case
nominative
the plain dictionary form — the doer of the sentence
genitive
the owner — whose it is
accusative
a specific, known object — whom or what
dative
direction or recipient — to where, to whom
locative
where it is; also having — mende bar, "I have it"
ablative
where it comes from; also "than" when comparing

The endings are the same ones the pronouns wear — that page explains when each case is used.

With an owner

One ownedSeveral owned
mymarşımmy marchmarşlarımmy marches
yourmarşıngyour marchmarşlarıngyour marches
his / hermarşıhis / her marchmarşlarıhis / her marches
ourmarşıbızour marchmarşlarıbızour marches
you all'smarşığızyou all's marchmarşlarığızyou all's marches
theirmarşlarıtheir marchmarşlarıtheir marches

The overlap in the last rows is real, not a mistake: marşları can mean "his / her marches", "their march", or "their marches" — context decides.