How do strong claims differ from weak claims?

In the field of title inheritance the difference is as follows. Strong claims are, as the name implies, the most useful type of claim. A strong claim can be pushed against anyone by almost anyone. The exception is that you cannot push a vassal or courtier woman's claim upon a title if the title uses Agnatic succession law. (If you are female, however, you may press your personal claims regardless of the title's succession law.) A weak claim can only be pushed if:

• the title holder is female and the claimant is male
• the title holder is in regency (due to imprisonment, incapability, youth, pilgrimage, or in hiding)
• the title is currently contested in another war
• or claimant is 2nd or 3rd in line to the title.