Do I need to fill my book before being able to call cog invasions? I am level 2 bloodsucker.
Some info for you. What Granjell told you is correct. Here's more information on it.
Each time you win a CJ battle, you get a summons. It is randomly chosen for the cog and type (cog, building or invasion). But there is a catch, you cannot get a summons for something you already have. This is a blessing in disguise really. There are 96 different summons in all and so as you collect summons, you fill in the ones you don't have yet.
To say it a different way, if you had all 96 summons and then used one to call a Big Cheese invasion (to make Trish all happy), the next time you CJ and win, you will get a summons for a Big Cheese invasion because it's the only one that is still empty. If you have all 96 and use 10 invasions from your book, then your next 10 CJ's will get you nothing but invasion summons.
The best advice to follow is this.. Never use your building and cog summons, as they open up spaces for a summons to fill. Instead, keep ALL building and cog summons and as you do, your odds for an invasion summons will increase. It's just how it works. If you only use invasion summons, then eventually, you'll fill all your cog and building summons and only have room for invasions.
There is actually a summons checklist that I made. I can try to put it up for you and then you can print it, laminate it and use a dry erase marker to track what you have (and rub off what you use). I print up copies, perm mark the cogs and buildings, and then use easy to ignore marks for the invasions, so that I can scribble as I gain/use them.
