Thermal dye transfer sheet and method for thermal dye transfer recording

A thermal dye transfer sheet having a dye layer provided on at least one side of a substrate, which is used for thermal dye transfer recording system carrying out recording by transferring a dye or dyes in the dye layer to a dye-receiving material by heating means, wherein the dye layer contains a pyrazolonemethine type dye of the following formula: wherein R1 and R2 can be respectively independently selected and are a lower alkyl group which may be substituted, a lower alkenyl group which may be substituted or an aryl group which may be substituted; and    R3 and R4 can be respectively independently selected and are a lower alkyl group which may be substituted, a dialkylamino group, a -COOR5 group or a -CONR6R7 group, in which R5 is a lower alkyl group which may be substituted, a lower alkenyl group which may be substituted or an aryl group which may be substituted and R6 and R7 can be respectively independently selected and are a hydrogen atom, a lower alkyl group which may be substituted, a lower alkenyl group which may be substituted or an aryl group which may be substituted.