With watermelon rind to cut off the hard green rind. Crust cut into smaller cubes, rhombs, cubes can be shaped and add to the pot. In another bowl pour 1 tsp with slide soda, pour 1 Cup of boiling water, then add 5 more cups of cold water - this solution pour the prepared crust. Peel stir and leave in the soda solution for 4-5 hours. The solution was then drained, rinsed with clean water peel and pour 30 min. of clean, cold water. Again to wash the crust and soak for 30 minutes in the water. Drain the water. Boil the syrup 600g sugar ( half of normal) and 3 glasses of water. In syrup folded crust and cook for 30 minutes. Leave the jam undisturbed for 12 hours. Then add 600g of sugar and boil the jam, stirring for another 30 min after boiling. Leave to stand for 12 hours. The third time, cook the jam for 20-30 minutes from the moment of boiling, this time, you can optionally add lemon juice, vanilla or lemon. Jam to cool and pour into sterile jars. Store in a cool place. Very tasty, unusual, beautiful jam turns out. Cook this recipe for many years. My adult children and grandchildren, and work colleagues really like the taste of this jam. Try to cook - you will not regret! Or rather regret that sooner threw the peel in the trash. Sorry no step by step photos. Somehow never thought to put this recipe, but I discarded crusts... it May be useful to someone this year, and to us, the watermelons may not bring.