Preheat oven to 400 degrees. Line a jelly roll pan with parchment paper. Place a clean tea towel on a flat surface.
In a mixing bowl, whisk together the flour, baking powder, matcha, and salt.
Beat the egg yolks with the sugar, milk, and vanilla until light and fluffy, about 3 minutes.
In a clean bowl with clean beaters, beat the egg whites with the cream of tartar until stiff peaks form.
Stir the flour into the egg yolk mixture. Take one third of the egg whites and stir into the yolk mixture. Gently fold in the rest of the egg whites, half at a time, until the mixture is no longer streaky. Spread the batter evenly into the prepared pan and bake for 8 minutes or until a toothpick inserted in the center comes out clean. Invert the pan onto the tea towel, remove the pan and peel off the parchment paper. Starting at the short edge, roll the cake to create a loose log, wrap lightly with the tea towel and let cool completely to room temperature.
When the cake has cooled, whip 1½ cups cream with the powdered sugar until stiff peaks form. Fold in ¾ cup chocolate chips.
Gently unroll the cake, spread the whipped cream over the top in an even layer and re-roll. Slice off a little from each edge of the roll to make the edges look clean and even. Place the roll on a rectangular serving platter.
In a small saucepan, combine ¾ cup chocolate chips with 3 tablespoons cream and the tamari. Heat over low, stirring, until the mixture is smooth and glossy.
Drizzle the chocolate sauce on top of the roll, allowing some of the chocolate to drip down the sides. Refrigerate the cake until ready to serve.
Place the raspberries and mint springs along the sides of the cake on the serving platter and serve.