Const LEFT_TOP_LOW As Integer = 3
Const LEFT_TOP_COLUMN As Integer = 2

Const BLACK_STONE As String = "●"
Const WHITE_STONE As String = "○"

Public stone_count As Integer
Public white_count As Integer
Public black_count As Integer

Sub start_button_Click()
    MsgBox "ゲームを始めます。楽しんでくださいね！"
    
    stone_count = 1
    white_count = 2
    black_count = 2
    
    Call clear_board
    
    Dim center_row As Integer
    Dim center_column As Integer
    
    center_row = LEFT_TOP_LOW + 3
    center_column = LEFT_TOP_COLUMN + 3
    
    Cells(center_row, center_column).Value = WHITE_STONE
    Cells(center_row, center_column + 1).Value = BLACK_STONE
    Cells(center_row + 1, center_column).Value = BLACK_STONE
    Cells(center_row + 1, center_column + 1).Value = WHITE_STONE
    
    Cells(1, 5).Value = "白の番です。"
    
    Cells(11, 2).Value = "白：" & white_count & "個"
    Cells(11, 5).Value = "黒：" & black_count & "個"

End Sub

Sub cell_DoubleClick(ByVal Target As Range, Cancel As Boolean)
    Dim cell_click_row As Integer
    Dim cell_click_column As Integer
    cell_click_row = Target.Row
    cell_click_column = Target.Column

    If is_within_board(cell_click_row, cell_click_column) Then
        Cancel = True
        
        If Cells(cell_click_row, cell_click_column).Value = "" Then
    
            Dim stone As String
            Dim reverse_stone As String
            
            Call set_current_stone(stone, reverse_stone)
            
            If change_check(cell_click_row, cell_click_column, stone, reverse_stone) Then
                Cells(Target.Row, Target.Column).Value = stone
                Call change_stone(cell_click_row, cell_click_column, stone, reverse_stone)
                
                stone_count = stone_count + 1
                
                If stone_count Mod 2 = 1 Then
                    Cells(1, 5).Value = "次は白の番です。"
                Else
                    Cells(1, 5).Value = "次は黒の番です。"
                End If
                
                white_count = 0
                black_count = 0
                
                Call count_stones
                
                Cells(11, 2).Value = "白：" & white_count & " 枚"
                Cells(11, 5).Value = "黒：" & black_count & " 枚"
            Else
                MsgBox "裏返す石がないのでここには置けません。"
            End If
        Else
            MsgBox "この場所にはすでに石があります。別の場所に置いてください。"
        End If
    Else
        MsgBox "盤の上に石を置いてください。"
    End If
End Sub

Function change_check(cell_row, cell_column, stone, reverse_stone)
    change_check = check_all_directions(cell_row, cell_column, stone, reverse_stone)
End Function

Sub change_stone(cell_row, cell_column, stone, reverse_stone)
    Call change_direction(cell_row, cell_column, stone, reverse_stone, AddressOf left_change_check, AddressOf change_left)
    ' Similar changes would be made for other directions as well, following the same pattern
End Sub
            i = i - 1
        Loop
        For j = cell_column - 1 To same_color_stone_column Step -1
            Cells(cell_row, j).Value = stone
        Next
    End If
    
    ' Similar changes would be made for other directions as well, following the same pattern
    ' Each directional check should be refactored to simplify the code and avoid redundancy
End Sub

Function left_change_check(cell_row, cell_column, stone, reverse_stone)
    left_change_check = False
    If cell_column - 2 >= LEFT_TOP_COLUMN Then
        If Cells(cell_row, cell_column - 1).Value = reverse_stone Then
            i = cell_column - 2
            Do While i >= LEFT_TOP_COLUMN
                If Cells(cell_row, i).Value = "" Then Exit Do
                If Cells(cell_row, i).Value = stone Then
                    left_change_check = True
                    Exit Do
                End If
                i = i - 1
            Loop
        End If
    End If
End Function

Function is_within_board(row As Integer, column As Integer) As Boolean
    is_within_board = (row >= 3 And row <= 10 And column >= 2 And column <= 9)
End Function

' The other directional check functions (right, up, down, diagonal) should also be similarly simplified