Sub Igeta_4(Work, LoopFlg)
    Dim I1Igeta, I2Igeta, I3Igeta, I4Igeta As Integer
    Dim J1Igeta, J2Igeta, J3Igeta, J4Igeta As Integer
    Dim I, J As Integer
    Dim Number As Integer
    Dim Igeta As Integer
    Dim Counter As Integer
    Dim S As String
    
    If LoopFlg <> "" Then Exit Sub  '確定文字がすでに見つかっているのでこのサブルーチンは実施しない
    
    For I1Igeta = 1 To 6  '行で井桁を見つける
        For I2Igeta = I1Igeta + 1 To 7
            For I3Igeta = I2Igeta + 1 To 8
                For I4Igeta = I3Igeta + 1 To 9
                    For Number = 1 To 9
                        Igeta = Number
                        Counter = 0
                        For J = 1 To 9
                            If InStr(Work(I1Igeta, J), Igeta) > 0 Or InStr(Work(I2Igeta, J), Igeta) > 0 Or InStr(Work(I3Igeta, J), Igeta) > 0 Or InStr(Work(I4Igeta, J), Igeta) > 0 Then
                                If (InStr(Work(I1Igeta, J), Igeta) > 0 And InStr(Work(I2Igeta, J), Igeta) > 0) Or (InStr(Work(I1Igeta, J), Igeta) > 0 And InStr(Work(I3Igeta, J), Igeta) > 0) Or (InStr(Work(I1Igeta, J), Igeta) > 0 And InStr(Work(I4Igeta, J), Igeta) > 0) Or (InStr(Work(I2Igeta, J), Igeta) > 0 And InStr(Work(I3Igeta, J), Igeta) > 0) Or (InStr(Work(I2Igeta, J), Igeta) > 0 And InStr(Work(I4Igeta, J), Igeta) > 0) Or (InStr(Work(I3Igeta, J), Igeta) > 0 And InStr(Work(I4Igeta, J), Igeta) > 0) Then
                                    Counter = Counter + 1
                                    J1Igeta = J2Igeta
                                    J2Igeta = J3Igeta
                                    J3Igeta = J4Igeta
                                    J4Igeta = J
                                Else
                                    Counter = 10
                                    Exit For
                                End If
                            End If
                        Next J
                        If Counter = 4 Then
                            For I = 1 To 9
                                If I = I1Igeta Or I = I2Igeta Or I = I3Igeta Or I = I4Igeta Then
                                Else
                                    S = Work(I, J1Igeta)
                                    S = Replace(S, Igeta, "")
                                    If S <> Work(I, J1Igeta) Then
                                        Work(I, J1Igeta) = S
                                        LoopFlg = "Igeta_4"
                                    End If
                                    S = Work(I, J2Igeta)
                                    S = Replace(S, Igeta, "")
                                    If S <> Work(I, J2Igeta) Then
                                        Work(I, J2Igeta) = S
                                        LoopFlg = "Igeta_4"
                                    End If
                                    S = Work(I, J3Igeta)
                                    S = Replace(S, Igeta, "")
                                    If S <> Work(I, J3Igeta) Then
                                        Work(I, J3Igeta) = S
                                        LoopFlg = "Igeta_4"
                                    End If
                                    S = Work(I, J4Igeta)
                                    S = Replace(S, Igeta, "")
                                    If S <> Work(I, J4Igeta) Then
                                        Work(I, J4Igeta) = S
                                        LoopFlg = "Igeta_4"
                                    End If
                                End If
                            Next I
                            If LoopFlg <> "" Then Exit Sub
                        End If
                    Next Number
                Next I4Igeta
            Next I3Igeta
        Next I2Igeta
    Next I1Igeta
    
            
    For J1Igeta = 1 To 6  '列で井桁を見つける
        For J2Igeta = J1Igeta + 1 To 7
            For J3Igeta = J2Igeta + 1 To 8
                For J4Igeta = J3Igeta + 1 To 9
                    For Number = 1 To 9
                        Igeta = Number
                        Counter = 0
                        For I = 1 To 9
                            If InStr(Work(I, J1Igeta), Igeta) > 0 Or InStr(Work(I, J2Igeta), Igeta) > 0 Or InStr(Work(I, J3Igeta), Igeta) > 0 Or InStr(Work(I, J4Igeta), Igeta) > 0 Then
                                If (InStr(Work(I, J1Igeta), Igeta) > 0 And InStr(Work(I, J2Igeta), Igeta) > 0) Or (InStr(Work(I, J1Igeta), Igeta) > 0 And InStr(Work(I, J3Igeta), Igeta) > 0) Or (InStr(Work(I, J1Igeta), Igeta) > 0 And InStr(Work(I, J4Igeta), Igeta) > 0) Or (InStr(Work(I, J2Igeta), Igeta) > 0 And InStr(Work(I, J3Igeta), Igeta) > 0) Or (InStr(Work(I, J2Igeta), Igeta) > 0 And InStr(Work(I, J4Igeta), Igeta) > 0) Or (InStr(Work(I, J3Igeta), Igeta) > 0 And InStr(Work(I, J4Igeta), Igeta) > 0) Then
                                    Counter = Counter + 1
                                    I1Igeta = I2Igeta
                                    I2Igeta = I3Igeta
                                    I3Igeta = I4Igeta
                                    I4Igeta = I
                                Else
                                    Counter = 10
                                    Exit For
                                End If
                            End If
                        Next I
                        If Counter = 4 Then
                            For J = 1 To 9
                                If J = J1Igeta Or J = J2Igeta Or J = J3Igeta Or J = J4Igeta Then
                                Else
                                    S = Work(I1Igeta, J)
                                    Work(I1Igeta, J) = Replace(S, Igeta, "")
                                    If S <> Work(I1Igeta, J) Then
                                        LoopFlg = "Igeta_4"
                                    End If
                                    S = Work(I2Igeta, J)
                                    Work(I2Igeta, J) = Replace(S, Igeta, "")
                                    If S <> Work(I2Igeta, J) Then
                                        LoopFlg = "Igeta_4"
                                    End If
                                    S = Work(I3Igeta, J)
                                    Work(I3Igeta, J) = Replace(S, Igeta, "")
                                    If S <> Work(I3Igeta, J) Then
                                        LoopFlg = "Igeta_4"
                                    End If
                                    S = Work(I4Igeta, J)
                                    Work(I4Igeta, J) = Replace(S, Igeta, "")
                                    If S <> Work(I4Igeta, J) Then
                                        LoopFlg = "Igeta_4"
                                    End If
                                End If
                            Next J
                            If LoopFlg <> "" Then Exit Sub
                        End If
                    Next Number
                Next J4Igeta
            Next J3Igeta
        Next J2Igeta
    Next J1Igeta

End Sub