If you don't know about checkers, you can check the Web and Google it to find a little more information about checkers.

And let me ask you about the game of checkers.

So, checkers is an interesting game.

Here's the typical board of the game of checkers.

What is this? Chess or checkers?

Three men. You don't know much about checkers, do you?

So, if you think checkers is partially observable, check this one.

It was Dietrichson's daughter Lola and it made me feel a little queer in the belly to.... have her sitting right there in the room, playing Chinese checkers, as if nothing was going to happen.

We stayed in old, crumbling, walled cities, in tiny little hotels, and we would climb up to the roof and drink Vinho Verde and watch the sun set and play checkers.

It is deterministic because your move and your opponent's move very clearly affect the state of the board in ways that have absolutely no stochasticity.

And apart from some very cryptic rules in checkers, which I won't really discuss here, the board basically tells you everything there is to know about checkers, so it's clearly fully observable.