A turbine bucket, comprising: a shank and a multi-wall blade coupled to and extending radially outward from the shank to a tip area, wherein the multi-wall blade comprises near-wall cooling channels and at least one central plenum, wherein the near-wall cooling channels comprise pressure side near-wall cooling channels, each pressure side near-wall cooling channel being arranged spanwise near a pressure side outside wall of the blade, and suction side near-wall cooling channels, each suction side near-wall cooling channel being arranged spanwise near a suction side outside wall of the blade, wherein the at least one central plenum is arranged between the pressure side near-wall cooling channels and the suction side near-wall cooling channels, the or each central plenum being arranged spanwise and being arranged to be adjacent the near-wall cooling channels but not adjacent an outside wall of the blade; the multi-wall blade characterized by: a forked passage cooling circuit (40, 140, 240), the forked passage cooling circuit (40, 140, 240) including a first leg (42, 142,242) and a second leg (46, 146, 246); and an air feed cavity (44, 144, 244) for supplying cooling air to the first leg (42, 142, 242) and the second leg (46, 146, 246) of the forked passage cooling circuit (40, 140, 240); wherein the first leg (42, 142, 242) of the forked passage cooling circuit (40, 140, 240) extends radially outward from and at least partially covers the at least one central plenum of the multi-wall blade, and wherein the second leg (46, 146, 246) of the forked passage cooling circuit (40, 140, 240) extends radially outward from and at least partially covers a first set of the near wall cooling channels in the multi-wall blade. a shank and a multi-wall blade coupled to and extending radially outward from the shank to a tip area, wherein the multi-wall blade comprises near-wall cooling channels and at least one central plenum, wherein the near-wall cooling channels comprise pressure side near-wall cooling channels, each pressure side near-wall cooling channel being arranged spanwise near a pressure side outside wall of the blade, and suction side near-wall cooling channels, each suction side near-wall cooling channel being arranged spanwise near a suction side outside wall of the blade, wherein the at least one central plenum is arranged between the pressure side near-wall cooling channels and the suction side near-wall cooling channels, the or each central plenum being arranged spanwise and being arranged to be adjacent the near-wall cooling channels but not adjacent an outside wall of the blade; the multi-wall blade characterized by: a forked passage cooling circuit (40, 140, 240), the forked passage cooling circuit (40, 140, 240) including a first leg (42, 142,242) and a second leg (46, 146, 246); and an air feed cavity (44, 144, 244) for supplying cooling air to the first leg (42, 142, 242) and the second leg (46, 146, 246) of the forked passage cooling circuit (40, 140, 240); wherein the first leg (42, 142, 242) of the forked passage cooling circuit (40, 140, 240) extends radially outward from and at least partially covers the at least one central plenum of the multi-wall blade, and wherein the second leg (46, 146, 246) of the forked passage cooling circuit (40, 140, 240) extends radially outward from and at least partially covers a first set of the near wall cooling channels in the multi-wall blade.