A rotor blade for a turbomachine, the rotor blade comprising: a main body having a shank , an airfoil extending radially outwardly from the shank , and a platform , the platform comprising a leading edge face axially spaced apart from a trailing edge face , and the main body comprising a pressure side slash face circumferentially spaced apart from a suction side slash face ; a slot defined within each of the pressure side slash face and the suction side slash face , wherein the slot of the pressure side slash face and the slot of the suction side slash face each comprises: an upstream end portion defining an end ; and a main body portion extending from the upstream end portion , the rotor blade being characterised in that the main body portion comprising a leading edge segment defined along the leading edge face , a platform segment defined along the platform , and a trailing edge segment defined along the trailing edge face ; the upstream end portion tapering from the end to the leading edge segment of the main body portion , the upstream end portion comprising a retention wall that covers a portion of the end and defines an opening that is arranged to slidably receive at least a portion of a seal into the slot ; the retention wall comprising an inner retention surface , the retention wall defining an offset from the opening . a main body having a shank , an airfoil extending radially outwardly from the shank , and a platform , the platform comprising a leading edge face axially spaced apart from a trailing edge face , and the main body comprising a pressure side slash face circumferentially spaced apart from a suction side slash face ; a slot defined within each of the pressure side slash face and the suction side slash face , wherein the slot of the pressure side slash face and the slot of the suction side slash face each comprises: an upstream end portion defining an end ; and a main body portion extending from the upstream end portion , the rotor blade being characterised in that the main body portion comprising a leading edge segment defined along the leading edge face , a platform segment defined along the platform , and a trailing edge segment defined along the trailing edge face ; the upstream end portion tapering from the end to the leading edge segment of the main body portion , the upstream end portion comprising a retention wall that covers a portion of the end and defines an opening that is arranged to slidably receive at least a portion of a seal into the slot ; the retention wall comprising an inner retention surface , the retention wall defining an offset from the opening . an upstream end portion defining an end ; and a main body portion extending from the upstream end portion , the rotor blade being characterised in that the main body portion comprising a leading edge segment defined along the leading edge face , a platform segment defined along the platform , and a trailing edge segment defined along the trailing edge face ; the upstream end portion tapering from the end to the leading edge segment of the main body portion , the upstream end portion comprising a retention wall that covers a portion of the end and defines an opening that is arranged to slidably receive at least a portion of a seal into the slot ; the retention wall comprising an inner retention surface , the retention wall defining an offset from the opening . <EOS>