A blade for a rotor of a turbine, in particular of a gas turbine, the blade comprising an airfoil, a shroud at the outer end of the airfoil and a platform at the inner end of the airfoil, wherein - the platform comprises a top plate adjacent to the airfoil, - the platform comprises a shank arranged below the top plate extending in the radial direction, - the platform comprises a fixing part arranged below the shank extending in the radial direction, - the shank comprises a front side and a back side facing in the circumferential direction, - the shank comprises a downstream side and an upstream side facing the axial direction, - an upstream wall projecting in the circumferential direction away form the shank extends from the top plate towards the fixing part and at least partially covers the upstream side of the shank, - a downstream wall projecting in the circumferential direction away form the shank extends from the top plate towards the fixing part and at least partially covers the downstream side of the shank, - at least one recess is provided in and, penetrates axially the upstream wall or through the downstream wall at least partially and is arranged in the shank region and the recess having an open side facing in the same direction as the direction of projection of the respective upstream or downstream wall (19, 20), characterized in that - the front side of the shank comprises a concave shape, and - the back side of the shank comprises a convex shape, - a circle tangenting the concave shaped front side and the convex shaped back side comprises a diameter C and at least one of the recesses comprises a width B in the radial direction at the corresponding outer end and a length A along the axial direction, wherein in particular the length A is given by the thickness of the corresponding wall section and - a depth D of the recess in the circumferential direction increases or decreases along the axial direction - a depth difference E is given as the difference between the maximum depth Dmax and the minimum depth Dmin, wherein - the length A of the recess is between 0 and (1.5 × C), and/or - the width B of the recess is between 0 and (0.7 × C), and/or - the depth difference E is between 0 and (0.45 × C). - the platform comprises a top plate adjacent to the airfoil, - the platform comprises a shank arranged below the top plate extending in the radial direction, - the platform comprises a fixing part arranged below the shank extending in the radial direction, - the shank comprises a front side and a back side facing in the circumferential direction, - the shank comprises a downstream side and an upstream side facing the axial direction, - an upstream wall projecting in the circumferential direction away form the shank extends from the top plate towards the fixing part and at least partially covers the upstream side of the shank, - a downstream wall projecting in the circumferential direction away form the shank extends from the top plate towards the fixing part and at least partially covers the downstream side of the shank, - at least one recess is provided in and, penetrates axially the upstream wall or through the downstream wall at least partially and is arranged in the shank region and the recess having an open side facing in the same direction as the direction of projection of the respective upstream or downstream wall (19, 20), - the front side of the shank comprises a concave shape, and - the back side of the shank comprises a convex shape, - a circle tangenting the concave shaped front side and the convex shaped back side comprises a diameter C and at least one of the recesses comprises a width B in the radial direction at the corresponding outer end and a length A along the axial direction, wherein in particular the length A is given by the thickness of the corresponding wall section and - a depth D of the recess in the circumferential direction increases or decreases along the axial direction - a depth difference E is given as the difference between the maximum depth Dmax and the minimum depth Dmin, wherein - the length A of the recess is between 0 and (1.5 × C), and/or - the width B of the recess is between 0 and (0.7 × C), and/or - the depth difference E is between 0 and (0.45 × C).