'How Chess Was Invented' (top to bottom, left to right):-
- BK: 'The castle has fallen!'
- [The White King (WK) waits for the Black King (BK) to enter]
- BK: 'Your reign is over, Sour King!'
- WK: 'Nevah!'
- BK: 'Crap'
No, I don't get it either. A related link, postmemes.com/how-chess-was-invented, explains exactly zip. The domain name at the bottom of the comic leads to Things in Squares: thingsinsquares.com/chess, but that doesn't help either. Looks like you had to be there.