Abstract: A blade has a flow passage forming plate that defines a part of a combustion gas flow passage. The flow passage forming plate has a plurality of back channels that open in a back end surface. A density of openings of the plurality of back channels in a middle region of the back end surface is higher than the density of openings of the plurality of back channels in at least one side region of a suction-side region and a pressure-side region of the back end surface. The density of openings is a ratio of a length of wetted perimeter of the plurality of back channels to an interval of openings of the plurality of back channels.