First, boil the syrup and leave it to cool!
Then put the confectionery cream, sugar, milk and vanilla in a bowl and beat with a mixer until you obtain a fluffy cream. It's preferable to have had the confectionery cream and milk in the fridge before beating them. Then put the cream mixture in the fridge for about 1 hour.
Unpack the cake layers and cut each into rectangles into 3 sections. (See photos).
The 1st needs to be 2″ (5 cm) wide, the 2nd 1 1/4″ (3 cm) wide and the 3rd - whatever's left. Next begin to assemble the cake: take the largest white rectangle, then place the middle rectangle of the black layer within it and finally the smallest part of the white layer inside in turn. Syrup well with the cooled syrup and smear with the cream mixture.
Then arrange cake layers in the reverse order: first the large part of the black layer, then middle part of the white layer within and the smallest part of the black layer.
Syrup again and smear with cream mixture. Keep arranging in this order until you run out of layers - in my case my cake had 6 layers. Smear well with cream on the top and sides, smooth out everywhere.
Draw chess squares lightly on top using a toothpick, then start to decorate. Decorate every other square with ground walnuts, the others with chocolate sprinkles, to obtain a chessboard (use a toothpick to help mark them out correctly).
If you have any chocolate sprinkles and ground walnuts left, mix them and use a spatula to distribute along the sides of the cake, from the bottom going up.
At the very top, decorate with the fondant chess pieces and put cake in the fridge for 24 hours.