1. A computer system for assessing life and death in a game of Go, the system for assessing life and death characterized in being provided with: (a) an input-receiving unit configured to run under control of a CPU of the computer system for receiving information concerning a board of Go-game, including player turns, an assessment area designated by a player, stones in the assessment area to be assessed including target stones constituting some or all of the stones to be assessed, from a storage device of a playing system; (b) an assessment unit configured to run under control of a CPU of the computer system for assessing, after the assessment area has been revised by being expanded, whether a group of said target stones is alive or dead; and (c) an output unit configured to run under control of a CPU of the computer system for outputting a result of a life and death assessment in the assessment unit, (d) wherein the assessment unit performs functions including: (e) expanding the assessment area, where an outside perimeter of an outside perimeter area has an end stone on a line second or third from a board edge, by extending the outside perimeter by positioning on the foregoing line, in adjoining fashion to the end stone, a number of stones of the same color as the outside perimeter so as to be connected to the stones of the outside perimeter, said number of stones corresponding to a number of lines between said end stone and the board edge, where the foregoing stones are necessary to convert part of the outside perimeter area, on the first or second line from the board edge, to an additional portion of the assessment area, thereby revising the assessment area; and (f) performing, when a group of stones in the revised assessment area has escaped, an assessment of said group of stones as being alive in cases where said group of stones is a group of said target stones, or, in cases where said group of stones is not a group of said target stones, executing a process for assessing life and death in which a condition is added that said group of target stones connected to said group of stones is alive while considering said group of stones as being uncapturable.