In a saucepan over medium heat, heat the cherries, wine, and sugar, stirring until the sugar dissolves.
Bring the mixture to a gentle boil. Immediately reduce the heat and let it simmer languidly for 5 minutes or so. Remove from the heat and let cool.
Stir the kirsch into the cherries and wine. Transfer the boozy liquid to a container with a tight-fitting lid, cover, and set aside at room temperature or in the fridge for 2 days.
Pour the liqueur, including the cherries, into sterilized bottles or jars with screw-top lids. Either stop the bottles with new corks or screw the lids onto the jars. Refrigerate the cherry liqueur until you consume it, preferably that same week.
Strain the cherry liqueur just before serving. Reserve the boozy cherries left behind to spoon over ice cream, layer with cake and whipped cream, plop atop rice pudding, or, well, we could go on, but you get the idea. Sip the chilled liqueur as-is or turn it into a spritzer* (see What You Need To Know below) and savor.