Questions

I have been playing the game again after a break, and I am running into a couple things that confuse me:

1) I keep finding that AI civs have open borders by default. I just met the Gauls on turn 152, and I can enter their territory on the next turn. Not the first time I have seen this. As best as I can see, other civs cannot enter my territory. So what gives here?

2) I am finding it unpredictable when an alliance will pull me into a war (or when it will pull an ally into a war). This morning, I was friends with Japan and allied with Rome, and Japan declared war on Rome. I was not pulled in. Why? And does this mean that if Japan declared war on me (after the friendship expired), then I would have been on my own?

To be clear, this was an economic, not a military alliance, but I believe the Civilopedia states that all alliances bring allies into a defensive war.

 

I suppose that the AI may jave not uet gotten Early Empire, which is what gives uou closed borders. Before that, your borders are always open. Of course, turn 125 feels really late to not have that, unless playing on marathon.

As to wars, my guess would be that you weren't pulled in because you were declared friends with Japan. I don't think you're allowed to declare war against friends, with the possible exception of an emergency.

 

Regarding the WAr stuff

You can't declare war on friends and/or allies, so you can't be pulled into a war with someone you have a Friendship with.

Regarding emergenices, that is only true fi it's a Betrayal Emergency, any other emergency you are exempt from voting (and so are they) and cannot partake if the recipient is a friend and or ally, again, unless it's an betrayal emergency which then allows anyone to join (including your allies, so if you are the recipient oh boy say goodbye to a lot of your allies)