Is the use case diagram correct? Tictactoe game

Question

I have made this use case diagram of a game called Tictactoe.

Please correct it if it is wrong.

Here is an image of the use case diagram:

Answer 1

• the difference between players is too small to differ players 1 and 2. There is only one actor - player
• Player does not check who won. This is NOT outer behaviour of the system and that means, it is not a use case.

So, the start use case diagram could be shown as:

But as we have only one actor, we don't need to show actors at all. And we can group the use cases into subsystems/packages. Maybe you haven't seen such UC diagrams, but in the UML standard 2.5 documentation there such ones, too.

The next step could be joining the state machine diagrams right here or as standalone diagrams.