In a large sauce pan, combine the cherries, currants, lemon juice, and kirsch. Crush the fruit and then bring the mixture to a boil.
Prepare your canning supplies. Bring the temperature of the glass jars up by processing them in hot water for several minutes, and heat a few cups of water in a small saucepan for the lids. Stir in the pectin until dissolved. Bring back to a boil, and then add in the sugar all at once. Boil hard for a minute longer.
Skim off any foam and ladle the hot jam into the hot jars, leaving 1/4″ headspace. Place the lids and bands on top, screwing on the bands just until fingertip-tight.
Place the full jars back into the boiling water and process 10 minutes.
Remove from the water and place the jars on a towel. Let the jars cool. The seals should suck down (you’ll hear a popping noise as they do).